CF546E Soldier and Traveling（最大流）

把每个点拆成两个点跑最大流即可。注意a的和可能和 b的和不相同！

#include <cstdio>#include <cstring>#include <algorithm>#include <queue>using namespace std;#define ll long long#define inf 0x3f3f3f3f#define N 300inline 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;}int n,m,a[N],h[N],num=1,T=210,tot=0,tot0=0,lev[N],cur[N],ans=0;struct edge{    int to,next,val;}data[2000];inline void add(int x,int y,int val){    data[++num].to=y;data[num].next=h[x];h[x]=num;data[num].val=val;    data[++num].to=x;data[num].next=h[y];h[y]=num;data[num].val=0;}inline bool bfs(){    queue<int>q;memset(lev,0,sizeof(lev));    q.push(0);lev[0]=1;    while(!q.empty()){        int x=q.front();q.pop();        for(int i=h[x];i;i=data[i].next){            int y=data[i].to;if(lev[y]||!data[i].val) continue;            lev[y]=lev[x]+1;q.push(y);        }    }return lev[T];}inline int dinic(int x,int low){    if(x==T) return low;int tmp=low;    for(int &i=cur[x];i;i=data[i].next){        int y=data[i].to;if(lev[y]!=lev[x]+1||!data[i].val) continue;        int res=dinic(y,min(tmp,data[i].val));        if(!res) lev[y]=0;else tmp-=res,data[i].val-=res,data[i^1].val+=res;        if(!tmp) return low;    }return low-tmp;}int main(){//  freopen("a.in","r",stdin);    n=read();m=read();    for(int i=1;i<=n;++i){        int x=read();tot+=x;add(0,i,x);add(i,i+n,inf);    }for(int i=1;i<=n;++i){        int x=read();tot0+=x;add(i+n,T,x);    }if(tot!=tot0){puts("NO");return 0;}    while(m--){        int x=read(),y=read();        add(x,n+y,inf);add(y,x+n,inf);    }while(bfs()){memcpy(cur,h,sizeof(cur));ans+=dinic(0,inf);}    if(ans!=tot){puts("NO");return 0;}puts("YES");    for(int x=1;x<=n;++x){        memset(a,0,sizeof(a));        for(int i=h[x];i;i=data[i].next){            int y=data[i].to-n;if(y==-n) continue;            a[y]=data[i^1].val;        }for(int i=1;i<n;++i) printf("%d ",a[i]);        printf("%d\n",a[n]);    }return 0;}