POJ 3468 A Simple Problem with Integers

最新推荐文章于 2023-10-02 10:26:46 发布

原创最新推荐文章于 2023-10-02 10:26:46 发布 · 239 阅读

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本文提供了一段使用C++语言实现线段树的数据结构，用于进行区间更新和区间查询操作。详细介绍了线段树的构建、更新和查询方法，并通过实例展示了如何高效地解决此类问题。

AC代码：

#include <iostream>
#include <cstdio>
using namespace std;

typedef long long ll;
const int N = 100005;

struct node{
    int l,r;
    ll add,sum;
}tree[N<<2];
ll a[N];

void pushup(int id){
    tree[id].sum = tree[id<<1].sum+tree[(id<<1)|1].sum;
}

void pushdown(int id){
    if(tree[id].add){
        ll tmp = tree[id].add;
        tree[id<<1].add += tmp;tree[(id<<1)|1].add += tmp;
        tree[id<<1].sum += (tree[id<<1].r-tree[id<<1].l+1)*tmp;
        tree[(id<<1)|1].sum += (tree[(id<<1)|1].r-tree[(id<<1)|1].l+1)*tmp;
        tree[id].add = 0;
    }
}

void build(int id,int l,int r){
    tree[id].l = l;
    tree[id].r = r;
    tree[id].add = 0;
    if(l == r){
        tree[id].sum = a[l];
        return ;
    }
    int mid = (l+r)>>1;
    build(id<<1,l,mid);
    build(id<<1|1,mid+1,r);
    pushup(id);
}

void update(int id,int l,int r,ll val){
    if(tree[id].l >= l && tree[id].r <= r){
        tree[id].add += val;
        tree[id].sum += (tree[id].r-tree[id].l+1)*val;
        return ;
    }
    pushdown(id);
    int mid = (tree[id].l+tree[id].r)>>1;
    if(l <= mid)
        update(id<<1,l,r,val);
    if(mid < r)
        update((id<<1)|1,l,r,val);
    pushup(id);
}

ll ans;

void query(int id,int l,int r){
    if(tree[id].l >= l && tree[id].r <= r){
        ans += tree[id].sum;
        return ;
    }
    pushdown(id);
    int mid = (tree[id].l+tree[id].r)>>1;
    if(l <= mid)
        query(id<<1,l,r);
    if(mid < r)
        query((id<<1)|1,l,r);
    pushup(id);
}

int main(){
    int n,m;
    while(~scanf("%d%d",&n,&m)){
        for(int i = 1; i <= n; i++)
            scanf("%lld",&a[i]);
        build(1,1,n);
        char op[10];
        int x,y;
        ll z;
        while(m--){
            scanf("%s",op);
            if(op[0] == 'Q'){
                ans = 0;
                scanf("%d%d",&x,&y);
                query(1,x,y);
                printf("%lld\n",ans);
            }
            else if(op[0] == 'C'){
                scanf("%d%d%lld",&x,&y,&z);
                update(1,x,y,z);
            }
        }
    }
    return 0;
}