Codeforces_732_D

http://codeforces.com/problemset/problem/732/D

二分查找。

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

int n,m,d[],a[],ok[];

int f(int x)
{
    memset(ok,,sizeof(ok));
    long long sum = ;
    for(int i = x;i >= ;i--)
    {
        if(d[i] && !ok[d[i]])
        {
            ok[d[i]] = ;
            sum += a[d[i]];
        }
        else if(sum)    sum--;
    }
    for(int i = ;i <= m;i++)
    {
        if(!ok[i])  return ;
    }
    if(sum) return ;
    return ;
}
int main()
{
    scanf("%d%d",&n,&m);
    for(int i = ;i <= n;i++)   scanf("%d",&d[i]);
    for(int i = ;i <= m;i++)   scanf("%d",&a[i]);
    int l = ,r = n;
    while(l < r)
    {
        int mid = (l+r)/;
        if(f(mid))  r = mid;
        else    l = mid+;
    }
    if(f(l))    printf("%d\n",l);
    else    printf("-1\n");
    return ;
}