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kmp

#include<bits/stdc++.h>
using namespace std;
const int N = 1e6+100;
int nex[N];
int s[N],t[N],c[N];
int n,m,p;
void getnex(){
    nex[0] = 0,nex[1] = 0;
    for(int i = 1;i < m;i ++){
        int j = nex[i];
        while(j&&t[i] != t[j]) j = nex[j];
        nex[i+1] = t[i] == t[j]?j+1:0;
    }
}
int kmp(int *S,int *T,int ls,int lt){
    int j = 0;
    int ret = 0;
    for(int i =0;i < ls;i ++){
        while(j && S[i]!= T[j]) j = nex[j];
        if(S[i] == T[j]) j++;
        if(j == lt) {ret ++;j = nex[j];}
    }
    return ret;
}

网络流：

include<bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
template<int N,typename T>
struct MaxFlow {
    int s,t,head[N],etot,que[N],qf,qe,dis[N],cur[N];
    struct Edge {int v,next; T cap;}g[501000];
    void init() {
        memset(head,-1,sizeof(head)); etot = 0;
    }
    void add_edge(int u,int v,T cap) {
        g[etot].v = v; g[etot].next = head[u]; g[etot].cap = cap; head[u] = etot ++;
        g[etot].v = u; g[etot].next = head[v]; g[etot].cap = 0; head[v] = etot ++;
    }
    bool bfs() {
        memset(dis,-1,sizeof(dis));
        memcpy(cur,head,sizeof(cur));
        dis[t] = N;
        qf = qe = 0;
        que[qe++] = t;
        while (qf!=qe) {
            int u = que[qf++];
            for (int i = head[u]; i != -1; i = g[i].next) {
                Edge &e = g[i];
                if (g[i^1].cap && dis[e.v] == -1) {
                    dis[e.v] = dis[u] - 1;
                    que[qe++] = e.v;
                }
            }
        }
        return dis[s] != -1;
    }
    T dfs(int u,T a) {
        if (u==t) return a;
        T flow = 0,f;
        for (int &i = cur[u]; i != -1; i = g[i].next) {
            Edge &e = g[i];
            if (e.cap && dis[e.v] > dis[u]) {
                f = dfs(e.v,std::min(a,e.cap));
                flow += f;
                e.cap -= f;
                g[i^1].cap += f;
                a -= f;
                if (a==0) break;
            }
        }
        if (flow==0) dis[u] = -1;
        return flow;
    }
    T dinic(int _s,int _t) {
        s = _s; t = _t;
        T flow = 0;
        while (bfs()) flow += dfs(s,(T)1e30);
        return flow;
    }
};

MaxFlow<10000,int> mf;
int n,m,s,t;
int cost[205];
void add_edge(int a,int b){
    mf.add_edge(2*a+1,2*b,INF);
    mf.add_edge(2*b+1,2*a,INF);
}

int main(){
    while(scanf("%d%d",&n,&m)!=EOF){
        mf.init();
        scanf("%d%d",&s,&t);
        for(int i= 1;i <= n;i ++) scanf("%d",&cost[i]);
        for(int i= 1;i <= m;i ++){
            int a,b;
            scanf("%d%d",&a,&b);
            add_edge(a,b);
        }
        for(int i= 1;i <= n;i ++){
            mf.add_edge(2*i,2*i+1,cost[i]);
            mf.add_edge(2*i+1,2*i,cost[i]);
        }
        int ans = mf.dinic(2*s,2*t+1);
        cout <<ans << endl;

    }
    return 0;
}

ac自动机

#include<bits/stdc++.h>
using namespace std;
const int N = 10000*50+100;
struct node_ac{
    int nex[N][26],fail[N],ed[N],L,root;
    int newnode(){
        for(int i= 0;i < 26; i++){
            nex[L][i]= -1;
        }
        ed[L] = 0;
        return L++;
    }
    void insert(char *s){
        int len = strlen(s);
        int p = root;
        for(int i= 0;i < len;i ++){
            int idx = s[i] - 'a';
            if(nex[p][idx] == -1){
                nex[p][idx] = newnode();
            }
            p = nex[p][idx];
        }
        ed[p] ++;
    }
    void init(){
        L = 0;
        root = newnode();
    }
    void build_ac(){
        queue<int> q;
        for(int i= 0;i < 26;i ++){
            if(nex[root][i]!= -1){
                q.push(nex[root][i]);
                fail[nex[root][i]] = root;
            }
            else nex[root][i] = root;
        }

        while(!q.empty()){
            int now = q.front();
            q.pop();
            for(int i= 0;i < 26;i ++){
                if(nex[now][i] == -1){
                    nex[now][i] = nex[fail[now]][i];
                }
                else {
                    fail[nex[now][i]] = nex[fail[now]][i];
                    q.push(nex[now][i]);
                }
            }
        }
    }
    int query(char *s){
        int ans = 0;
        int len = strlen(s);
        int p = root;
        for(int i= 0;i < len;i ++){

            int idx = s[i] - 'a';
            p = nex[p][idx];
            int tmp = p;
            while(tmp!= root&&ed[tmp]!= -1){
                ans += ed[tmp];
                ed[tmp] = -1;
                tmp = fail[tmp];
            }
        }
        return ans;
    }

}AC;

int main(){

    int T;
    scanf("%d",&T);
    for(int cas = 1;cas <= T;cas ++){
        int n;
        AC.init();
        scanf("%d",&n);
        for(int i= 1;i <= n;i ++){
            char st[100];
            scanf("%s",st);
            AC.insert(st);
        }
        AC.build_ac();
        char st[1000005];
        scanf("%s",st);
        printf("%d\n",AC.query(st));
    }
    return 0;
}

inline int clz(int x){return __builtin_clz(x);}
inline int clz(ll x){return __builtin_clzll(x);}
inline int lg2(int x){return !x ? -1 : 31-clz(x);}
inline int lg2(ll x){return !x ? -1 : 63-clz(x);}

高斯消元

long long solve(){
    memset(a,0,sizeof(a));
    for(int i = 0;i < vp.size();i ++){
        for(int j = 59;j >=0;j --){
            if((vp[i]>>j)&1){
                if(a[j]){
                    vp[i] ^= a[j];
                }
                else{
                    a[j] = vp[i];
                    break;
                }
            }
        }
    }
    for(int i = 0;i < 60;i ++){
        for(int j = i+1;j < 60;j ++){
            if((a[j]>>i)&1) a[j] ^= a[i];
        }
    }
    long long ans = 0;
    for(int i = 0;i < 60;i ++) ans ^= a[i];
    return ans;
}

最小费用流

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


const int N = 55;

template<int N,typename T>
struct CostFlow {
    int s,t,head[N],etot,prevv[N],preve[N],inq[N],que[N],qf,qe;
    T dis[N];
    struct Edge {int v,next; T cap,cost;} g[501000];
    void init() {
        memset(head,-1,sizeof(head)); etot = 0;
    }
    void add_edge(int u,int v,T cap,T cost) {
        //cout << u <<' ' << v << ' ' << cap << ' ' << cost << endl;
        g[etot].v = v; g[etot].cap = cap; g[etot].cost = cost; g[etot].next = head[u]; head[u] = etot ++;
        g[etot].v = u; g[etot].cap = 0; g[etot].cost = -cost; g[etot].next = head[v]; head[v] = etot ++;
    }
    void mcmf(int _s,int _t,T myflow,T &cost,T &flow) {
        s = _s; t = _t; cost = flow = 0;
        while (true) {
            for (int i = 0; i < N; i ++) dis[i] = (T)1e10;
            dis[s] = 0;
            qf = qe = 0;
            que[qe++] = s;
            while (qf!=qe) {
                int u = que[qf++]; inq[u] = 0; if (qf==N) qf = 0;
                for (int i = head[u]; i != -1; i = g[i].next) {
                    Edge &e = g[i];
                    if (e.cap && dis[e.v]>dis[u]+e.cost) {
                        dis[e.v] = dis[u]+e.cost;
                        prevv[e.v] = u; preve[e.v] = i;
                        if (!inq[e.v]) {
                            que[qe++] = e.v;
                            if (qe==N) qe = 0;
                            inq[e.v] = 1;
                        }
                    }
                }
            }
            if (dis[t]==T(1e10)) break;
            T f = (T)1e30;
            for (int u = t; u != s; u = prevv[u])
                f = std::min(f,g[preve[u]].cap);
            f = std::min(f,myflow);
            cost += f*dis[t];
            flow += f;
            myflow -= f;
            if(myflow == 0) return;
            for (int u = t; u != s; u = prevv[u])
                g[preve[u]].cap -= f,g[preve[u]^1].cap += f;
        }
    }
};
CostFlow<50005,int> MF;
int n,m,k;
int need[N][N],cap[N][N];
int main(){
    while(scanf("%d%d%d",&n,&m,&k)!=EOF){
        if(n == 0 && m == 0 && k == 0) break;
        for(int i =1;i <= n;i ++){
            for(int j= 1;j <= k;j ++){
                scanf("%d",&need[i][j]);
            }
        }
        for(int i= 1;i <= m;i ++){
            for(int j = 1;j <= k;j ++){
                scanf("%d",&cap[i][j]);
            }
        }
        int cost = 0;
        bool ans = true;
        for(int i= 1;i <= k;i ++){

            MF.init();
            for(int j = 1;j <= n;j ++){
                for(int p= 1;p <= m;p ++){
                    int c;
                    scanf("%d",&c);
                    //cout << "@@@@@@@@@@" << i << ' ' << c<<endl;
                    MF.add_edge(p,m+j,105,c);
                }
            }if(ans == false) continue;
            for(int j= 1;j <= m;j ++){
                MF.add_edge(0,j,cap[j][i],0);
            }
            int myflow = 0;
            for(int j= 1;j <= n;j ++){
                myflow += need[j][i];
                MF.add_edge(m+j,n+m+1,need[j][i],0);
            }
            int costnow,flow;
            MF.mcmf(0,n+m+1,myflow,costnow,flow);
            //cout << "###" << myflow << ' ' << flow << ' ' << costnow << endl;
            if(flow!=myflow){ans = false;}
            else cost += costnow;
        }
        if(ans) cout << cost<<endl;
        else puts("-1");


    }
    return 0;
}