Median of Two Sorted Arrays

1package pkg5leetcode.interview150;2 3/*4 * Median of Two Sorted Arrays | LC 45 * APPROACH: Binary search smaller array partition; O(log min(n,m)).6 * COMPLEXITY: Time O(log(min(n,m))), Space O(1)7 */8public class interview150_LC4MedianTwoSortedArrays {9    static double findMedianSortedArrays(int[] a, int[] b) {10        if (a.length > b.length) return findMedianSortedArrays(b, a);11        int n = a.length, m = b.length, lo = 0, hi = n;12        while (lo <= hi) {13            int i = (lo + hi) / 2, j = (n + m + 1) / 2 - i;14            int aLo = i == 0 ? Integer.MIN_VALUE : a[i - 1];15            int aHi = i == n ? Integer.MAX_VALUE : a[i];16            int bLo = j == 0 ? Integer.MIN_VALUE : b[j - 1];17            int bHi = j == m ? Integer.MAX_VALUE : b[j];18            if (aLo <= bHi && bLo <= aHi) {19                if ((n + m) % 2 == 0) return (Math.max(aLo, bLo) + Math.min(aHi, bHi)) / 2.0;20                return Math.max(aLo, bLo);21            }22            if (aLo > bHi) hi = i - 1;23            else lo = i + 1;24        }25        return 0;26    }27 28    public static void main(String[] args) {29        check(findMedianSortedArrays(new int[]{1, 3}, new int[]{2}) == 2.0, "case1");30        check(findMedianSortedArrays(new int[]{1, 2}, new int[]{3, 4}) == 2.5, "case2");31        System.out.println("all tests passed");32    }33 34    static void check(boolean cond, String name) {35        if (!cond) throw new AssertionError("FAILED: " + name);36        System.out.println("  PASS " + name);37    }38}