C++ | Leetcode C++题解之第398题随机数索引
题目：
题解：
class Solution {
vector<int> &nums;
public:
Solution(vector<int> &nums) : nums(nums) {}
int pick(int target) {
int ans;
for (int i = 0, cnt = 0; i < nums.size(); ++i) {
if (nums[i] == target) {
++cnt; // 第 cnt 次遇到 target
if (rand() % cnt == 0) {
ans = i;
}
}
}
return ans;
}
};