uva_624_CD

裸的背包题目+路径回溯#include <cstdio>#include <cstring>#include <algorithm>using namespace std;#define MAXN    21#define MAXV    10001int v[MAXN], dp[MAXV], pre[MAXN][MAXV];void back_track(const int &idx, const int &cur_v){        for(int i = idx-1; i >= 1; i --) {                if( 1 == pre[i][ cur_v-v[idx] ] ) {                        back_track(i, cur_v-v[idx]); break;                }        }        printf("%d ", v[idx]);}void dynamic_programming(const int &n, const int &max_v){        memset(pre, -1, sizeof(pre));        memset(dp, 0, sizeof(dp)); dp[0] = 1;        for(int i = 1; i <= n; i ++) {                for(int j = max_v; j >= v[i]; j --) {                        if( dp[ j-v[i] ] ) {                                dp[j] = pre[i][j] = 1;                        }                }        }        for(int i = max_v; i >= 0; i --) {                if( !dp[i] ) {                        continue;                }                for(int j = n; j >= 1; j --) {                        if( 1 == pre[j][i] ) {                                back_track(j, i);                                 printf("sum:%d\n", i); return;                        }                }        }}int main(int argc, char const *argv[]){#ifndef ONLINE_JUDGE        freopen("test.in", "r", stdin);#endif        int max_v, n;        while( ~scanf("%d %d", &max_v, &n) ) {                for(int i = 1; i <= n; i ++) {                        scanf("%d", &v[i]);                }                dynamic_programming(n, max_v);        }        return 0;}