面试题 16.10. 生存人数

C++

class Solution {
public:
    int maxAliveYear(vector<int>& birth, vector<int>& death) {
        int ans = 0, length = birth.size();
        vector<int> cnt(105,0);
        
        for(int i = 0; i < length; i++){
            cnt[birth[i] - 1900]++;
            cnt[death[i] - 1900 + 1]--;
        }
        int preSum = 0, maxLive = 0;
        for(int i = 0; i < 105; i++){
            preSum += cnt[i]; // 前缀和/累加
            if(preSum > maxLive){
                maxLive = preSum;
                ans = i;
            }
        }
        return ans + 1900;
    }
};

Python

class Solution:
    def maxAliveYear(self, birth: List[int], death: List[int]) -> int:
        birth_total = [0 for _ in range(105)]
        death_total = [0 for _ in range(105)]
        length = len(birth)
        
        # 记录这100年每年出生和死亡的人数
        for i in range(length): 
            birth_total[birth[i] - 1900] += 1
            death_total[death[i] - 1900 + 1] += 1
        # 记录这100年每年累计出生和累计死亡的人数
        for i in range(1,101): 
            birth_total[i] += birth_total[i - 1]
            death_total[i] += death_total[i - 1]

        live = 0
        for i in range(101):
            #print(birth_total[i] - death_total[i], live, i + 1900)
            if birth_total[i] - death_total[i] > live:
                live = birth_total[i] - death_total[i]
                re = i + 1900
        return re

我是傻逼…没好好审题，手动调试了1个小时，1909年死亡的人在1909年是计数的…