365天挑战LeetCode1000题——Day 034 每日一题 + 二分查找 12

---

731. 我的日程安排表 II

首刷自解

class MyCalendarTwo {
public:
    map<int, int> calendar;
    MyCalendarTwo() {
        
    }
    
    bool book(int start, int end) {
        calendar[start]++;
        calendar[end]--;
        int count = 0;
        for (auto& c : calendar) {
            count += c.second;
            if (count > 2) {
                calendar[start]--;
                calendar[end]++;
                return false;
            }
        }
        return true;
    }
};

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * MyCalendarTwo* obj = new MyCalendarTwo();
 * bool param_1 = obj->book(start,end);
 */

---

81. 搜索旋转排序数组 II

首刷自解

class Solution {
public:
    bool search(vector<int>& nums, int target) {
        int left = 0;
        while (nums[left] == nums.back()) {
            left++;
            // 如果都是同一个值，那么会扫描到尾部
            if (left == nums.size()) return nums.back() == target;
        }
        
        // 求最小值
        int l = left, r = nums.size() - 1;
        while (l < r) {
            int m = (l + r) >> 1;
            if (nums[m] <= nums.back()) r = m;
            else l = m + 1;
        }
        if (target == nums.back()) return true;
        if (target > nums. back()) {
            r--;
            l = left;
        }
        else {
            r = nums.size() - 1;
        }
        while (l < r) {
            int m = (l + r) >> 1;
            if (nums[m] >= target) r = m;
            else l = m + 1;
        }
        return nums[l] == target;
    }
};

---

162. 寻找峰值

首刷自解

class Solution {
public:
    int findPeakElement(vector<int>& nums) {
        if (nums.size() == 1) return 0;
        int l = 1, r = nums.size() - 2;
        if (nums[l - 1] > nums[l]) return l - 1;
        if (nums[r + 1] > nums[r]) return r + 1;
        int ans;
        while (l <= r) {
            int m = (l + r) >> 1;
            if (nums[m] > nums[m - 1] && nums[m] > nums[m + 1]) return m;
            if (nums[m] < nums[m + 1]) l = m + 1;
            else r = m;
        }
        return l;
    }
};

---