codeforces 302B. Eugeny and Play List

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题意：求时间num是在第几首歌，看到这么大的数据，就用二分做，做不出来，二分实在是掌握的不好，然后就用搜索做,之后有尝试了二分的方法，切记不一样的题，边界的判断是不一样的

#include <iostream>#include <cstdio>#include <cstring>using namespace std;const int MAXN = 100005;long long arr[MAXN],brr[MAXN],crr[MAXN];int n,m;int main(){    scanf("%d%d",&n,&m);    arr[0] = 0;    for (int i = 1; i <= n; i++){        long long a,n;        scanf("%lld%lld",&brr[i],&crr[i]);        arr[i] = arr[i-1] + brr[i]*crr[i];    }    int cur=0;    long long num,top=0;    for (int i = 1; i <= m; i++){        scanf("%lld",&num);        while (num > top){            cur++;            top += brr[cur] * crr[cur];        }        printf("%d\n",cur);    }    return 0;}

#include <cstdio>#include <cstring>#include <iostream>using namespace std;const int MAXN = 200000;long long a[MAXN];int n,m;int find(long long num){    int left=0,right=n+1;    while (right > left+1){        int mid = (left+right)/2;        if (a[mid]<num)            left = mid;        else right = mid;;    }    return right;}int main(){    while (scanf("%d%d",&n,&m) != EOF){        long long a,b;        a[0] = 0;        for (int i = 1; i <= n; i++){            scanf("%lld%lld",&a,&b);            a[i] = a[i-1] + a*b;        }        long long num;        for(int i = 1; i <= m; i++){            scanf("%lld",&num);            int pos=find(num);            printf("%d\n",pos);         }       }    return 0;       }