day31 打卡455.分发饼干 376. 摆动序列 53. 最大子数组和

455.分发饼干

class Solution {
    public int findContentChildren(int[] g, int[] s) {
        int count = 0;
        Arrays.sort(g);
        Arrays.sort(s);
        int gIndex = 0;
        int sIndedx = 0;
        while (gIndex<g.length && sIndedx<s.length) {
            if (g[gIndex]<=s[sIndedx]) {
                gIndex++;
                sIndedx++;
                count++;
            } else {
                sIndedx++;
            }
        }
        return count;
    }
}

376. 摆动序列

376题目链接

class Solution {
    public int wiggleMaxLength(int[] nums) {
        if (nums == null || nums.length == 0) return 0;
        if (nums.length == 1) return 1;
        int preDif = 0;
        int curDif = 0;
        int count = 1;
        for (int i=0; i<nums.length-1 ; i++) {
            curDif = nums[i+1] - nums[i];
            if ((preDif<=0 && curDif>0) || (preDif>=0 && curDif<0)) {
                count++;
                preDif = curDif;
            }
        }
        return count;
    }
}

53. 最大子数组和

53题目链接

class Solution {
    public int maxSubArray(int[] nums) {
        int result = Integer.MIN_VALUE;
        int count = 0;
        for (int i = 0 ; i<nums.length ; i++) {
            count += nums[i];
            if (count>result) result = count;
            if (count<0) count = 0;
        }
        return result;
    }
}