HDOJ 1258

#include<map>
#include<string>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 20
using namespace std;
int a[MAXN], temp[MAXN], vis[MAXN];
int T, N, flag, sum;
string ss;
char str[MAXN];
map<string, int>mp;
bool cmp(int a, int b){return a > b;}
void dfs(int dep, int idx){
if(sum > T) return;
if(idx == N && sum != T) return;
if(sum == T){
flag ++;
if(flag == 1) printf("Sums of %d:\n", T);
for(int i = 0; i < dep; i ++) str[i] = temp[i];
ss.clear();
ss = str;
mp[ss]++;
if(mp[ss] == 1){
for(int i = 0; i < dep-1; i ++) printf("%d+", temp[i]);
printf("%d\n", temp[dep-1]);
}
return;
}
for(int i = idx; i < N; i ++){
if(!vis[i]){
vis[i] = 1;
temp[dep] = a[i];
sum += a[i];
dfs(dep+1, i+1);
sum -= a[i];
vis[i] = 0;
}
}
}
int main(){
int tt;
/* freopen("in.c", "r", stdin); */
while(~scanf("%d%d", &T, &N) && N+T){
tt = 0;
memset(vis, 0, sizeof(vis));
for(int i = 0; i < N; i ++) scanf("%d", a+i),tt += a[i];
if(tt < T){
printf("Sums of %d:\nNONE\n", T);
continue;
}
sort(a, a+N, cmp);
mp.clear();
sum = flag = 0;
dfs(0, 0);
if(!flag) printf("Sums of %d:\nNONE\n", T);
}
return 0;
}