剑指 Offer 14- II. 剪绳子 II

力扣

class Solution {
public:
    int cuttingRope(int n) {       
        if (n <= 3) return n - 1;
        long ret = 1;
        if (n % 3 == 1){
            ret = 4;
            n = n - 4;
        }
        if (n % 3 == 2){
            ret = 2;
            n = n - 2;
        }
        while (n) {
            ret = ret * 3 % 1000000007;            
            n = n - 3;
        }
        return (int)ret;
    }
};