noip模板整理

NOIP模板整理

By:Licher

数论

快速幂

洛谷P1266

int quickPower(int a, int b)//是求a的b次方
{
    int ans = 1, base = a;//ans为答案,base为a^(2^n)
    while(b > 0)//b是一个变化的二进制数,如果还没有用完
    {
        if(b & 1)//&是位运算,b&1表示b在二进制下最后一位是不是1,如果是:
        {
            ans *= base;//把ans乘上对应的a^(2^n)
            //ans %= p; //如果需要取模
        }
        base *= base;//base自乘,由a^(2^n)变成a^(2^(n+1))
        //base %= p; //同上,取模运算
        b >>= 1;//位运算,b右移一位,如101变成10(把最右边的1移掉了),10010变成1001。现在b在二进制下最后一位是刚刚的倒数第二位。结合上面b & 1食用更佳
    }
    return ans;
}

高精度

洛谷P1601

加法

string add(string str1,string str2)//只能是两个正数相加
{
    string str;
    int len1=str1.length();
    int len2=str2.length();
    //前面补0,弄成长度相同
    if(len1<len2)
    {
        for(int i=1;i<=len2-len1;i++)
           str1="0"+str1;
    }
    else
    {
        for(int i=1;i<=len1-len2;i++)
           str2="0"+str2;
    }
    len1=str1.length();
    int cf=0;
    int temp;
    for(int i=len1-1;i>=0;i--)
    {
        temp=str1[i]-'0'+str2[i]-'0'+cf;
        cf=temp/10;
        temp%=10;
        str=char(temp+'0')+str;
    }
    if(cf!=0)  str=char(cf+'0')+str;
    return str;
}

减法

string sub(string str1,string str2)////只能是两个正数相减,而且要大减小
{
    string str;
    int tmp=str1.length()-str2.length();
    int cf=0;
    for(int i=str2.length()-1;i>=0;i--)
    {
        if(str1[tmp+i]<str2[i]+cf)
        {
            str=char(str1[tmp+i]-str2[i]-cf+'0'+10)+str;
            cf=1;
        }
        else
        {
            str=char(str1[tmp+i]-str2[i]-cf+'0')+str;
            cf=0;
        }
    }
    for(int i=tmp-1;i>=0;i--)
    {
        if(str1[i]-cf>='0')
        {
            str=char(str1[i]-cf)+str;
            cf=0;
        }
        else
        {
            str=char(str1[i]-cf+10)+str;
            cf=1;
        }
    }
    str.erase(0,str.find_first_not_of('0'));//去除结果中多余的前导0
    return str;
}

乘法

string mul(string str1,string str2)//只能是两个正数相乘
{
    string str;
    int len1=str1.length();
    int len2=str2.length();
    string tempstr;
    for(int i=len2-1;i>=0;i--)
    {
        tempstr="";
        int temp=str2[i]-'0';
        int t=0;
        int cf=0;
        if(temp!=0)
        {
            for(int j=1;j<=len2-1-i;j++)
              tempstr+="0";
            for(int j=len1-1;j>=0;j--)
            {
                t=(temp*(str1[j]-'0')+cf)%10;
                cf=(temp*(str1[j]-'0')+cf)/10;
                tempstr=char(t+'0')+tempstr;
            }
            if(cf!=0) tempstr=char(cf+'0')+tempstr;
        }
        str=add(str,tempstr);
    }
    str.erase(0,str.find_first_not_of('0'));
    return str;
}

除法

//compare比较函数:相等返回0,大于返回1,小于返回-1
int compare(string str1,string str2)
{
    if(str1.length()>str2.length()) return 1;
    else if(str1.length()<str2.length())  return -1;
    else return str1.compare(str2);
}

//两个正数相除,商为quotient,余数为residue
//需要高精度减法和乘法
void div(string str1,string str2,string &quotient,string &residue)
{
    quotient=residue="";//清空
    if(str2=="0")//判断除数是否为0
    {
        quotient=residue="ERROR";
        return;
    }
    if(str1=="0")//判断被除数是否为0
    {
        quotient=residue="0";
        return;
    }
    int res=compare(str1,str2);
    if(res<0)
    {
        quotient="0";
        residue=str1;
        return;
    }
    else if(res==0)
    {
        quotient="1";
        residue="0";
        return;
    }
    else
    {
        int len1=str1.length();
        int len2=str2.length();
        string tempstr;
        tempstr.append(str1,0,len2-1);
        for(int i=len2-1;i<len1;i++)
        {
            tempstr=tempstr+str1[i];
            tempstr.erase(0,tempstr.find_first_not_of('0'));
            if(tempstr.empty())
              tempstr="0";
            for(char ch='9';ch>='0';ch--)//试商
            {
                string str,tmp;
                str=str+ch;
                tmp=mul(str2,str);
                if(compare(tmp,tempstr)<=0)//试商成功
                {
                    quotient=quotient+ch;
                    tempstr=sub(tempstr,tmp);
                    break;
                }
            }
        }
        residue=tempstr;
    }
    quotient.erase(0,quotient.find_first_not_of('0'));
    if(quotient.empty()) quotient="0";
}

线性筛素数

洛谷P1601

埃氏筛法 O(nlglgn)

const int MAXN = 1000000;
void get_list()
{
    int i, j;
    for (i=0; i<MAXN; i++) prime[i] = 1;
    prime[0] = prime[1] = 0;
    for (i=2; i<MAXN; i++)
    {
        if (!prime[i]) continue;
        for (j=i*2; j<MAXN; j+=i) prime[j] = 0;
    }
}

最大公约数(gcd)

int gcd(int a,int b)
{
    if(a==0) return bl
    return gcd(b%a,a);
}

最小公倍数(lcm)

int lcm(int a,int b)
{
    int c = a/gcd(a,b);
    return c*b;
}

扩展欧几里德

同余方程 P1082

int exgcd(int a,int b,int &x,int &y){
    if (b==0){
        x=1,y=0;
        return a;
    }
    int d=gcd(b,a%b,y,x);
    y-=a/b*x;
    return d;
}

数据结构

并查集

洛谷P3367

int n, m;
int fa[200005];

int find(int x)    //寻找祖宗节点
{
    if (fa[x] == x)
        return x;
    return fa[x] = find(fa[x]);
}

void add(int x, int y)
{
    fa[find(x)] = find(y);//将y的祖宗节点变成x祖宗节点的父节点
}

int main()
{
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        fa[i] = i; //初始化,使每一个节点的父节点都是自己
    }
    for (int i = 1; i <= m; i++)
    {
        int z, x, y;
        cin >> z >> x >> y;
        if (z == 1)
            add(x, y);
        if (z == 2)
            if (find(x) == find(y))
                cout << 'Y' << endl;
            else
                cout << 'N' << endl;
    }
}

树状数组

单点修改

洛谷P3374

int n,m;
int tree_array[1000010];//树状数组

int lowbit(int x){return x&(-x);}

void update(int point,int num)//在序列第point的位置加num
{
    while(point<=n)
    {
        tree_array[point] += num;
        point += lowbit(point);
    }
}

int sum(int point)//计算序列中1~point的和
{
    int res=0;
    while(point > 0)
    {
        res += tree_array[point];
        point -= lowbit(point);
    }
    return res;
}

int main()
{
    scanf("%d %d",&n,&m);
    for(int i = 1;i<=n;i++)
    {
        int num;
        scanf("%d",&num);
        update(i,num);//初始值是0,直接更新即可
    }
    for(int i = 1;i<=m;i++)
    {
        int z,x,y;
        scanf("%d %d %d",&z,&x,&y);
        if(z == 1)
        {
            update(x,y);
        }
        if(z == 2)
        {
            int ans = sum(y)-sum(x-1);//用[1,y]的和减去[1,x-1]的和就是[x,y]的和
            printf("%d\n",ans);
        }
    }
    return 0;
}

区间修改

洛谷P3368
差分处理

int  n,m;
int a[500005];
int t[2000005];
int lowbit(int x){
    return x&(-x);
}

void update(int i,int num)
{
    for(;i<=n;i+=lowbit(i))
    {
        t[i] += num;
    }
}

int search(int i)
{
    int res = 0;
    for(;i;i-=lowbit(i))
    {
        res += t[i];
    }
    return res;
}

int main()
{
    scanf("%d%d",&n,&m);
    for(int i = 1;i<=n;i++)
    {
        scanf("%d",a+i);
        update(i,a[i]-a[i-1]);
    }
    for(int i = 1;i<=m;i++)
    {
        int type;
        scanf("%d",&type);
        if(type==1)
        {
            int l,r,k;
            scanf("%d%d%d",&l,&r,&k);
            update(l,k);
            update(r+1,-k);
        }
        if(type==2)
        {
            int x;
            scanf("%d",&x);
            printf("%d\n",search(x));
        }
    }
    return 0;
 }

线段树

洛谷P3372

long long n,m;
long long a[100010];
struct TREE
{
    long long l,r,num,lazy;
}tree[400050];

void build(long long left,long long right,long long index)
{
    tree[index].l = left;
    tree[index].r = right;
    if(left == right)
    {
        tree[index].num = a[left];
        return;
    }
    long long mid = (tree[index].l+tree[index].r)/2;
    build(left,mid,index*2);
    build(mid+1,right,index*2+1);
    tree[index].num = tree[index*2].num+tree[index*2+1].num;
}

void spread(long long index)
{
    if(tree[index].lazy)
    {
        long long nowlazy = tree[index].lazy;
        tree[index*2].num += nowlazy*(tree[index*2].r-tree[index*2].l+1);
        tree[index*2+1].num += nowlazy*(tree[index*2+1].r-tree[index*2+1].l+1);
        tree[index*2].lazy += nowlazy;
        tree[index*2+1].lazy += nowlazy;
        tree[index].lazy = 0;
    }
}

void add(long long index,long long left,long long right,long long value)
{
    if(left<=tree[index].l && right>=tree[index].r)
    {
        tree[index].num += value*(tree[index].r-tree[index].l+1);
        tree[index].lazy += value;
        return;
    }
    spread(index);
    long long mid = (tree[index].l+tree[index].r)/2;
    if(left <= mid) add(index*2,left,right,value);
    if(right > mid) add(index*2+1,left,right,value);
    tree[index].num = tree[index*2].num + tree[index*2+1].num;
}

long long search(long long index,long long left,long long right)
{
    if((left <= tree[index].l) && (right >= tree[index].r))
    {
        return tree[index].num;
    }
    spread(index);
    long long mid = (tree[index].l+tree[index].r)/2;
    long long res = 0;
    if(left <= mid) res += search(index*2,left,right);
    if(right > mid) res += search(index*2+1,left,right);
    return res;
}

int main()
{
    n = read();
    m = read();
    for(long long i = 1;i<=n;i++)
    {
        a[i] = read();
    }
    build(1,n,1);
    for(long long i = 1;i<=m;i++)
    {
        long long type,x,y,k;
        type = read();
        if(type == 1)
        {
            x = read();
            y = read();
            k = read();
            add(1,x,y,k);
        }
        if(type == 2)
        {
            x = read();
            y = read();
            long long ans = search(1,x,y);
            printf("%lld\n",ans);
        }
    }
    return 0;
}

ST表

洛谷P3865

int n,m;
ll a[100010];
ll f[100010][21];
int l,r;
void init()
{
    for(int i = 1;i<=n;i++)
    {
        f[i][0] = a[i];
    }
    for(int i = 1;i<21;i++)
    {
        for(int j = 1;j+(1<<i)-1<=n;j++)
        {
            f[j][i] = max(f[j][i-1],f[j+(1<<(i-1))][i-1]);
        }
    }
}

int search()
{
    int k = log2(r-l+1);//<cmath>头文件不要忘
    return max(f[l][k],f[r-(1<<k)+1][k]);
}

int main()
{
    scanf("%d%d",&n,&m);
    for(int i = 1;i<=n;i++) scanf("%lld",a+i);
    init();
    while(m--)
    {
        scanf("%d%d",&l,&r);
        printf("%d\n",search());
    }
    return 0;
}

图论

单源最短路

洛谷P3371

dijkstra

int n,m,s;
ll d[100010];
int num;
int head[100010];
bool vis[100010];
struct EDGE{
    int v,ne;
    ll w;
}e[200010];
priority_queue<P,vector<P>,greater<P> >q;
void add(int x,int y,ll z)
{
    num++;
    e[num].ne = head[x];
    e[num].v = y;
    e[num].w = z;
    head[x] = num;
}

inline int read() {
    int X=0,w=1; char c=getchar();
    while (c<'0'||c>'9') { if (c=='-') w=-1; c=getchar(); }
    while (c>='0'&&c<='9') X=(X<<3)+(X<<1)+c-'0',c=getchar();
    return X*w;
}

void dij()
{
    d[1] = 0;
    for(int i = 2;i<=n;i++)
    {
        d[i] = INF;
    }
    q.push(make_pair(0,1));
    while(!q.empty())
    {
        int x = q.top().second;
        q.pop();
        if(vis[x]) continue;
        vis[x] = 1;
        for(int i = head[x];i;i = e[i].ne)
        {
            int v = e[i].v;
            ll w = e[i].w;
            if(d[v]>d[x]+w)
            {
                d[v] = d[x]+w;
                q.push(make_pair(d[v],v));
            }
        }
    }
}

int main()
{
    n = read();
    m = read();
    s = read();
    for(int i = 1;i<=m;i++)
    {
        int x,y;
        ll z;
        x = read();
        y = read();
        z = read();
        add(x,y,z);
    }
    dij();
    for(int i = 1;i<=n;i++)
    {
        printf("%lld ",d[i]);
    }
    return 0;
}

SPFA

int n,m,s;
int num,head[10010];
ll d[10010];
bool v[10010];
queue<int> q;
struct EDGE{
    int v,ne,w;
}e[500010];
void add(int x,int y,int z)
{
    num++;
    e[num].v = y;
    e[num].w = z;
    e[num].ne = head[x];
    head[x] = num;
}

void spfa()
{
    for(int i = 1;i<=n;i++)
    {
        d[i] = INF;
    }
    d[s] = 0;
    v[s] = 1;
    q.push(s);
    while(!q.empty())
    {
        int x = q.front();
        q.pop();
        v[x] = 0;
        for(int i = head[x];i;i=e[i].ne)
        {
            int ver = e[i].v;
            int w = e[i].w;
            if(d[ver]>d[x]+w)
            {
                d[ver] = d[x]+w;
                if(!v[ver])
                {
                    v[ver] = 1;
                    q.push(ver);
                }
            }
        }
    }
}

int main()
{
    n=read();m=read();s=read();
    for(int i = 1;i<=m;i++)
    {
        int x,y,z;
        x=read();y=read();z=read();
        add(x,y,z);
    }
    spfa();
    for(int i = 1;i<=n;i++)
    {
        printf("%lld ",d[i]);
    }
    return 0;
}

多源最短路

floyd

int d[310][310],n,m;

void floyd()
{
    for(int k=1;k<=n;k++)
        for(int i=1;i<=n;i++)
            for(int j=1;j<=n;j++)
                d[i][j] = min(d[i][j],d[i][k]+d[k][j]);
}

int main()
{
    cin>>n>>m;
    //把d数组初始化为邻接矩阵
    memset(d,0x3f,sizeof(d));
    for(int i=1;i<-=n;i++) d[i][i] = 0;
    for(int i=1;i<=m;i++)
    {
        int x,y,z;
        scanf("%d%d%d",&x,&y,&z);
        d[x][y] = min(d[x][y],z);
    }
    floyd();
   //d[x][y]就是x到y的最短距离
    return 0;
}

最小生成树

kruskal

洛谷P3366

int n,m;
int fa[5005];
int ans = 0;
struct EDGE{
    int x,y,w;
    friend bool operator<(EDGE A,EDGE B)
    {
        return A.w>B.w;
    }
};
priority_queue<EDGE> q;

int find(int x)
{
    if(fa[x]==x)return x;
    return fa[x] = find(fa[x]);
}

void add(int x,int y)
{
    fa[find(x)] = find(y);
}

bool kurscal(){
    int cnt = 0;
    while(!q.empty())
    {
        int x = q.top().x;
        int y = q.top().y;
        int w = q.top().w;
        q.pop();
        if(find(x)!=find(y))
        {
            ans += w;
            add(x,y);
            cnt++;
        }
    }
    return cnt==n-1;
}

int main()
{
    scanf("%d%d",&n,&m);
    for(int i = 1;i<=n;i++) fa[i] = i;
    for(int i = 1;i<=m;i++)
    {
        EDGE e;
        scanf("%d%d%d",&e.x,&e.y,&e.w);
        q.push(e);
    }
    if(kurscal()){
        printf("%d",ans);
    }else{
        puts("orz");
    }
    return 0;
}

奇技淫巧

快读

inline int read()
{
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}

转载于:https://www.cnblogs.com/lichers/p/9917164.html

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