java 363.矩形的最大总和不大于K（＃1）.java

Posted 2021-05-08

public class Solution {
    // private int maxSubArrayLessK(int[] arr, int k) {   Wrong Answer for [27, 16, 24, 28, 7, -7, -3, -20, 23, 5, 13, 15, 15, 26, -19] -100
    //     int end = 0;
    //     int sum = 0, res = Integer.MIN_VALUE;
    //     int len = arr.length;
    //     for (int start = 0; start < len; start++) {
    //         while (end < len && sum + arr[end] <= k) {
    //             sum += arr[end++];
    //             res = Math.max(res, sum);
    //         }
    //         if (end == len && sum <= k) {
    //         	res = Math.max(res, sum);
    //         }
    //         sum -= arr[start];
    //     }
    //     return res;
    // }
    
    private int maxSubArrayLessK(int[] a , int k){
        int max = Integer.MIN_VALUE;
        int sumj = 0;
        TreeSet<Integer> s = new TreeSet();
        s.add(0);

        for(int i=0;i<a.length;i++){
            int t = sumj + a[i];
            sumj = t;
            Integer gap = s.ceiling(sumj - k);
            if(gap != null) max = Math.max(max, sumj - gap);
            s.add(t);
        }
        return max;
    }
    public int maxSumSubmatrix(int[][] matrix, int k) {
        int row = matrix.length, col = matrix[0].length;
        int res = Integer.MIN_VALUE;
        for (int left = 0; left < col; left++) {
            int[] temp = new int[row];
            for (int right = left; right < col; right++) {
                for(int i = 0; i < row; i++) {
                    temp[i] += matrix[i][right];
                }
                res = Math.max(res, maxSubArrayLessK(temp, k));
            }
        }
        return res;
    }
}

/*
[[5,-4,-3,4],[-3,-4,4,5],[5,1,5,-4]]
8
Expected Answer 8
*/

public class Solution {

    public static int maxSumSubArrayNoGreaterThanK(int[] s, int k) {
        int len     = s.length;
        int ans     = Integer.MIN_VALUE;
        int nums[] = new int[len];
        nums[0] = s[0];
        for(int i=1;i<len;i++){
            nums[i] = nums[i-1] + s[i];
        }

        for(int i=0;i<len;i++){
            for(int j=i;j<len;j++){
                int sum;
                if(i==0) sum = nums[j];
                else sum = nums[j] - nums[i-1];
                if(sum > ans && sum <= k)
                    ans = sum;
            }
        }
        return ans;
    }


    public int maxSumSubmatrix(int[][] matrix, int k) {
        int cols    = matrix[0].length;
        int rows    = matrix.length;
        int maxSum  = Integer.MIN_VALUE;

        for (int leftCol = 0; leftCol < cols; leftCol++) {
            int[] tmp = new int[rows];
            for (int rightCol = leftCol; rightCol < cols; rightCol++) {
                for (int l = 0; l < rows; l++) {
                    tmp[l] += matrix[l][rightCol];
                }
                int currentResult = maxSumSubArrayNoGreaterThanK(tmp,k);
                if (currentResult > maxSum) {
                    maxSum = currentResult;
                }
            }
        }
        return maxSum;
    }
}