Submission #9035476

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Source Code Expand

 // ===================================
//   author: M_sea
//   website: http://m-sea-blog.com/
// ===================================
#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#define re register
using namespace std;

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*10+c-'0',c=getchar();
    return X*w;
}

const int N=100000+10;

int n,m;
int f[N],s[N];

int main() {
    n=read(),m=read();
    f[1]=1;
    for (re int i=1;i<=n;++i) s[i]=1;
    for (re int i=1;i<=m;++i) {
        int x=read(),y=read();
        if (f[x]) {
            if (s[x]==1) f[x]=0,f[y]=1;
            else f[y]=1;
        }
        --s[x],++s[y];
    }
    int ans=0;
    for (re int i=1;i<=n;++i) ans+=f[i];
    printf("%d\n",ans);
    return 0;
}

Submission Info

Judge Result