Subsequence

http://poj.org/problem?id=3061 

#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <algorithm>
using namespace std;
#define LL long long
const int maxn = 100010;
const int inf = 0x3f3f3f3f;
LL a[maxn], b[maxn];
int main(){
    int t;
    //freopen("in.txt", "r", stdin);
    scanf("%d", &t);
    while(t--){
        int n, s;
        scanf("%d %d", &n, &s);
        b[0] = 0;
        for(int i = 1; i <= n; i++) {
            scanf("%lld", &a[i]);
            b[i] = b[i - 1] + a[i];
        }
        int ans = inf;
        for(int i = 1; i <= n; i++){
            if(b[i] < s) continue;
            int temp = b[i] - s;
            int id = lower_bound(b + 1, b + 1 + n, temp) - b;
            if(b[id] == temp) while(b[id + 1] == temp) id++;
            else{
                id--;
            }
            //cout<<i<<"  ----------  "<<id<<" =++"<<endl;
            ans = min(ans, i - id);
        }
        if(ans == inf) ans = 0;
        printf("%d
", ans);
    }
}

尺取～

#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <algorithm>
using namespace std;
#define LL long long
const int maxn = 100010;
const int inf = 0x3f3f3f3f;
LL a[maxn];
int main(){
    int t;
    //freopen("in.txt", "r", stdin);
    scanf("%d", &t);
    while(t--){
        int n, s;
        scanf("%d %d", &n, &s);
        for(int i = 0; i < n; i++) scanf("%lld", &a[i]);
        int i = 0, j = 0;
        int sum = 0;
        int ans = inf;
        while(1){
            while(sum < s && j < n) sum += a[j++];
            if(sum < s) break;
            ans = min(ans, j - i);
            sum -= a[i++];
        }
        if(ans == inf) ans = 0;
        printf("%d
", ans);
    }
}