HDU 5808 Price List Strike Back bitset优化的背包。。水过去了

http://acm.hdu.edu.cn/showproblem.php?pid=5808

用bitset<120>dp，表示dp[0] = true，表示0出现过，dp[100] = true表示100这个数字出现过。

对于每一个新的数字，val，有转移方程，

dp = dp | (dp << val)

比如现在0000101，然后枚举了2进来，0000101 | 0010100

那个区间是暴力扫过去的，是水过去的，关键学了下bitset优化的背包。

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <bitset>
vector<int>vc[222];
const int maxn = 20000 + 20;
int dis[maxn];
char ans[100000 + 20];
void init() {
    for (int i = 1; i <= 100; ++i) vc[i].clear();
}
void work() {
    init();
    int n, m;
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; ++i) {
        int price;
        scanf("%d", &price);
        vc[price].push_back(i);
    }
    for (int i = 1; i <= n; ++i) {
        scanf("%d", &dis[i]);
    }
    for (int i = 1; i <= m; ++i) {
        int L, R, mostDis, sum;
        scanf("%d%d%d%d", &L, &R, &mostDis, &sum);
        bitset<120>dp;
        dp[0] = 1;
        bool flag = false;
        for (int j = 1; j <= 100 && !flag; ++j) {
            if (vc[j].size() == 0) continue;
            int lo = lower_bound(vc[j].begin(), vc[j].end(), L) - vc[j].begin();
            int up = upper_bound(vc[j].begin(), vc[j].end(), R) - vc[j].begin();
            up--;
            for (int k = lo; k <= up; ++k) {
                if (dis[vc[j][k]] > mostDis) continue;
                dp = dp | (dp << j);
                if (dp[sum]) {
                    flag = true;
                    break;
                }
            }
        }
        if (!flag) {
            ans[i] = '1';
        } else ans[i] = '0';
    }
    ans[m + 1] = '';
    printf("%s
", ans + 1);
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    int t;
    scanf("%d", &t);
    while (t--) work();
    return 0;
}