硬币组合问题

//硬币的找零问题，给定一个数值，求使得最少的硬币数组合成所要的数值int CoinChange(vector<int> coins,int len,int sum){vector<int> dp(sum+1,sum+1);dp[0]=0;//设定为0for(int i=1;i<=sum;i++){for(int j=0;j<len;j++){if(coins[j]<=i)dp[i]=min(dp[i],dp[i-coins[j]]+1);}}return dp[sum]>sum?-1:dp[sum];}//dp[i][j]=sum(dp[i-1][j-k*coins[i-1]]),k=0,1,2,...j/coins[i-1]int CoinsCombination(vector<int> &a,int len,int sum){vector<vector<int>> dp(len+1);vector<int> vec(sum+1,0);for(int i=0;i<=len;i++)dp[i]=vec;for(int i=0;i<=len;i++)dp[i][0]=1;//每一种硬币组合成数值0的方法为1for(int i=1;i<=len;i++){for(int j=1;j<=sum;j++){dp[i][j]=0;for(int k=0;k<=j/a[i-1];k++)dp[i][j]+=dp[i-1][j-k*a[i-1]];}}return dp[len][sum];}