sum it up（wrong answer）

最新推荐文章于 2021-12-21 13:53:38 发布

原创最新推荐文章于 2021-12-21 13:53:38 发布 · 539 阅读

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本文探讨了给定整数列表求所有可能组合等于特定总和的问题。通过递归深度优先搜索算法解决，并确保输出结果中各组合为唯一且按降序排列。适用于算法竞赛及面试准备。

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#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define maxn 1005
#define inf 0x3f3f3f3f
int t,n;
int a[maxn];
bool vis[maxn];
int b[maxn];
int flag;
void dfs(int sum,int cur,int cnt){
  //if(cur>n||cnt>n)return ;
  if(sum>t)return;
  if(sum==t){
        flag=1;
    for(int i=1;i<cur-1;i++)
        printf("%d%s",b[i],"+");
    printf("%d\n",b[cur-1]);
    return ;
  }
  //if(cur>n||cnt>n)return ;
  for(int i=cnt;i<=n;i++){
    //if(!vis[i]){
        //vis[i]=true;
        b[cur]=a[i];
        dfs(sum+b[cur],cur+1,i+1);
        //vis[i]=false;
        while(i+1<=n&&a[i]==a[i+1])i++;
   // }
  }
}
int main()
{
   freopen("in.txt","r",stdin);
    while(scanf("%d%d",&t,&n)!=EOF&&n&&t){
          //  memset(vis,0,sizeof vis);
            flag=0;
        for(int i=1;i<=n;i++){
            scanf("%d",&a[i]);
        }
    printf("%s%d%s\n","Sum of ",t,":");
        dfs(0,1,1);
        if(flag==0)printf("%s\n","NONE");
    }
}

Sum It Up

Time Limit:1000MS Memory Limit:32768KB 64bit IO Format:%I64d & %I64u

Submit Status Practice HDU 1258

Description

Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t=4, n=6, and the list is [4,3,2,2,1,1], then there are four different sums that equal 4: 4,3+1,2+2, and 2+1+1.(A number can be used within a sum as many times as it appears in the list, and a single number counts as a sum.) Your job is to solve this problem in general.

Input

The input will contain one or more test cases, one per line. Each test case contains t, the total, followed by n, the number of integers in the list, followed by n integers x1,...,xn. If n=0 it signals the end of the input; otherwise, t will be a positive integer less than 1000, n will be an integer between 1 and 12(inclusive), and x1,...,xn will be positive integers less than 100. All numbers will be separated by exactly one space. The numbers in each list appear in nonincreasing order, and there may be repetitions.

Output

For each test case, first output a line containing 'Sums of', the total, and a colon. Then output each sum, one per line; if there are no sums, output the line 'NONE'. The numbers within each sum must appear in nonincreasing order. A number may be repeated in the sum as many times as it was repeated in the original list. The sums themselves must be sorted in decreasing order based on the numbers appearing in the sum. In other words, the sums must be sorted by their first number; sums with the same first number must be sorted by their second number; sums with the same first two numbers must be sorted by their third number; and so on. Within each test case, all sums must be distince; the same sum connot appear twice.

Sample Input

     
       4 6 4 3 2 2 1 1
5 3 2 1 1
400 12 50 50 50 50 50 50 25 25 25 25 25 25
0 0

Sample Output

     
       Sums of 4:
4
3+1
2+2
2+1+1
Sums of 5:
NONE
Sums of 400:
50+50+50+50+50+50+25+25+25+25
50+50+50+50+50+25+25+25+25+25+25