POJ 2184 DP 01背包+完全背包

链接：

http://poj.org/problem?id=2184

代码：

#include <map>
#include <set>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define mp make_pair
#define lson l,m,rt<<1  
#define rson m+1,r,rt<<1|1 
typedef long long ll;
typedef vector<int> VI;
typedef pair<int, int> PII;
const ll MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const int MAXN = 2e5 + 7;
// head

int n;
int s[110], f[110];
int dp[MAXN];

int main() {
    int n;
    cin >> n;
    rep(i, 1, n + 1) cin >> s[i] >> f[i];
    rep(i, 0, MAXN) dp[i] = -INF;
    dp[100000] = 0;
    rep(i, 1, n + 1) {
        if (s[i] < 0 && f[i] < 0) continue;
        if (s[i] > 0) {
            per(j, s[i], 200001) if (dp[j - s[i]] > -INF)
                dp[j] = max(dp[j], dp[j - s[i]] + f[i]);
        }
        else {
            rep(j, s[i], s[i] + 200001) if (dp[j - s[i]] > -INF)
                dp[j] = max(dp[j], dp[j - s[i]] + f[i]);
        }
    }
    int ans = 0;
    rep(i, 100000, 200001) if (dp[i] >= 0)
        ans = max(ans, dp[i] + i - 100000);
    cout << ans << endl;
    return 0;
}