leetcode-470. 用 Rand7() 实现 Rand10()

题目

代码

#include <iostream>
#include <vector>
using namespace std;

int rand10() {
/*	double tn = (double)rand7() / 7;
	tn = tn * 9 + 1;
	return (int)tn;*/
//    return (rand7() + rand7() + rand7() + rand7() + rand7() + rand7() + rand7() + rand7() + rand7() + rand7()) % 10 +1;    
	int row, col, idx;
	do{
		col = rand7();
		row = rand7();
		idx = col + (row - 1) * 7;
	}while(idx > 40);
	return 1 + (idx - 1) % 10; 
}

int main(){
	int res;
	res = rand10();
	cout<<res;
	return 0;
}