UVA1607 与非门电路&&二分答案

题目

看了白书，还看了这个题解

check最后return的下标忘了改，卡了一起

#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
const int N=233333;
struct gate{int x,y,z;}a[N*2];
int n,m;

int check(int x){
    for (int i=n-x;i<n;i++) a[i].z=1;
    for (int i=0;i<n-x;i++) a[i].z=0;
    for (int i=n+1;i<=n+m;i++){
        a[i].z=!(a[a[i].x].z&a[a[i].y].z);
    }
    return a[m+n].z;
}

int main(){
    //freopen("fuck.in","r",stdin);
    int T;scanf("%d",&T);
    for (;T--;){
        scanf("%d%d",&n,&m);
        memset(a,0,sizeof(a));
        for (int i=1;i<=m;i++){
            //n-1~0为n个输入，n+1~n+m 为m个gate
            int x,y;scanf("%d%d",&x,&y);
            a[n+i].x=x+n;
            a[n+i].y=y+n;
        }
        int a0=check(0),a1=check(n),ans;
        if (a0==a1)ans=0;//常数
        else{
            int L=0,R=n;
            while(L<R){
                //if (L==R){ans=L;break;}
                int mid=(L+R)>>1;
                if (check(mid)==a1)R=mid;
                else L=mid+1;
            } ans=L;
        }
        for (int i=1;i<ans;i++)putchar('1');
        if (ans>=1)printf("x");
        for (int i=ans+1;i<=n;i++)putchar('0');
        puts("");
    }
    return 0;
}