poj 1564 Sum It Up

原题链接：http://poj.org/problem?id=1564
dfs。。

#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<vector>#include<queue>#include<set>using std::set;using std::sort;using std::pair;using std::swap;using std::queue;using std::multiset;#define pb(e) push_back(e)#define sz(c) (int)(c).size()#define mp(a, b) make_pair(a, b)#define all(c) (c).begin(), (c).end()#define iter(c) decltype((c).begin())#define cls(arr, val) memset(arr, val, sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for(int i = 0; i < (int)n; i++)#define tr(c, i) for(iter(c) i = (c).begin(); i != (c).end(); ++i)const int N = 1010;const int INF = 0x3f3f3f3f;typedef unsigned long long ull;bool f;int n, tot, tar, A[N], B[N];void dfs(int cur, int ret, int k) {    if (ret == tar) {        f = true;        for (int i = 0; i < k; i++) {            if (!i) printf("%d", B[i]);            else printf("+%d", B[i]);        }        putchar('\n');        return;    }    for (int i = cur; i < n; i++) {        if (i == cur || A[i] != A[i - 1]) { // 判重            B[k] = A[i];            dfs(i + 1, ret + A[i], k + 1);        }    }}int main() {#ifdef LOCAL    freopen("in.txt", "r", stdin);    freopen("out.txt", "w+", stdout);#endif    while (~scanf("%d %d", &tar, &n), n) {        f = false;        rep(i, n) scanf("%d", &A[i]);        printf("Sums of %d:\n", tar);        dfs(0, 0, 0);        if (!f) { puts("NONE"); continue; }    }    return 0;}