add MedianOfTwoSortedArrays.cpp

daiwb · daiwb · commit 8f5bc07d9297 · 2013-01-21T17:42:07.000-08:00
diff --git a/LeetCode/MedianOfTwoSortedArrays.cpp b/LeetCode/MedianOfTwoSortedArrays.cpp
@@ -0,0 +1,41 @@
+#include <iostream>
+#include <climits>
+using namespace std;
+
+class Solution {
+public:
+    double findMedianSortedArrays(int A[], int m, int B[], int n) {
+        int mid = (m + n - 1) / 2;
+        int st = 0, ed = m - 1, i = 0, j = 0;
+        while (st <= ed) {
+            i = (st + ed) / 2;
+            j = mid - i;
+
+            int b1 = getVal(B, n, j - 1), b2 = getVal(B, n, j);
+            if (A[i] >= b1 && A[i] <= b2) {
+                break;
+            } else if (A[i] < b1) {
+                st = i + 1;
+            } else if (A[i] > b2) {
+                ed = i - 1;
+            }
+        }
+
+        if (st <= ed) {
+            if ((m + n) & 1) {
+                return A[i];
+            } else {
+                int o = min(getVal(A, m, i + 1), getVal(B, n, j));
+                return (A[i] + o) * 0.5;
+            }
+        } else {
+            return findMedianSortedArrays(B, n, A, m);
+        }
+    }
+
+    int getVal(int a[], int n, int idx) {
+        if (idx < 0) return INT_MIN;
+        else if (idx >= n) return INT_MAX;
+        else return a[idx];
+    }
+};
