10-最长连续递增序列-贪心算法

题目链接

class Solution {
    public int findLengthOfLCIS(int[] nums) {
        // return findLengthOfLCIS1(nums);
         return findLengthOfLCIS2(nums);
    }
    // 1.贪心算法。速度2ms
    public int findLengthOfLCIS1(int[] nums) {
        int start = 0;
        int max = 1; 
        for(int i = 1; i < nums.length; i++) {
            if(nums[i] <= nums[i-1]) {
                start = i;
            }
            max = Math.max(max, i-start+1); // 两边植树取中间
        }
        return max;
    }
    // 2.栈。速度 8ms或7ms
    public int findLengthOfLCIS2(int[] nums) {
        Stack<Integer> stack = new Stack<>();
        int max = 0;
        for(int i = 0; i < nums.length; i++) {
            while(!stack.isEmpty() && stack.peek() >= nums[i]) {
                stack = new Stack<>();
            }
            stack.push(nums[i]);
            max = Math.max(max, stack.size());
        }
        return max;
    }
}