[POJ 3624]Charm Bracelet

#include<iostream>#include<cstdio>#include<cstring>using namespace std;const int maxn = 3402+20;const int maxm = 12880+20;int W[maxn];        // weightint D[maxn];        // desirabilityint f[2][maxm];int main() {    int N, M;    while( cin >> N >> M ) {        memset( f, 0, sizeof(f) );        for(int i=1; i<=N; ++i) {            cin >> W[i] >> D[i];        }        for(int i=1; i<=N; ++i) {            for(int j=1; j<=M; j++) {                f[i%2][j] = f[(i-1)%2][j];                if( j-W[i]>=0 ) {                    f[i%2][j] = max( f[i%2][j], f[(i-1)%2][j-W[i]] + D[i] );                }            }        }        cout << f[N%2][M] << endl;    }    return 0;}