算法笔记：最大子数组

public class Solution {
    public static int maxSubSlow(int[] array) {
        int result = Integer.MIN_VALUE;
        for (int i = 0; i < array.length; i++) {
            int t = 0;
            for (int j = i; j < array.length; j++) {
                t += array[j];
                if (t > result)
                    result = t;
            }
        }
        return result;
    }

    private static int crossSub(int[] array, int min, int mid, int max) {
        int leftResult = array[mid];
        for (int i = mid, t = 0; i >= min; i--) {
            t += array[i];
            if (t > leftResult)
                leftResult = t;
        }

        int rightResult = array[mid + 1];
        for (int i = mid + 1, t = 0; i <= max; i++) {
            t += array[i];
            if (t > rightResult)
                rightResult = t;
        }

        return Math.max(leftResult, rightResult);
    }

    public static int maxSubDC(int[] array, int min, int max) {
        if (min == max)
            return array[min];
        int mid = (max + min) / 2;

        int leftMax = maxSubDC(array, min, mid);
        int rightMax = maxSubDC(array, mid + 1, max);
        int crossMax = crossSub(array, min, mid, max);

        return Math.max(crossMax, Math.max(leftMax, rightMax));
    }

    public static int maxSubDP(int[] array) {
        int result = Integer.MIN_VALUE;
        for (int i = 0, t = 0; i < array.length; i++) {
            t += array[i];
            if (t > result)
                result = t;
            if (t < 0)
                t = 0;
        }
        return result;
    }
}