剪绳子

int cutRope(int number) {
     vector<int> memo(number + 1, 1);
     return helpCutRope(memo, number);
 }
 int helpCutRope(vector<int> &memo, int number)
 {
     if(number == 1) return 1;
     if(memo[number] > 1) return memo[number]; 
     for(int i = 1; i < number; i++)
     {
         memo[number] = max( memo[number], i * ((number - i) <= 
                            helpCutRope(memo, number - i) ? 
                            helpCutRope(memo, number - i) : number - i));
     }
     return memo[number];
 }

int cutRope(int number)
 {
     vector<int> dp(number + 1, 1);
     for(int i = 2; i <= number; i++)
     {
         for(int j = 1; j < i; j++)
         {
             dp[i] = max(dp[i], j * (dp[i - j] <= (i - j) ? i - j : dp[i - j]));
         }
     }
     return dp[number];
 }