add: FindTheInsertionIndex

Author: Jer3myYu

java/Binary Search/FindTheInsertionIndex.java

@@ -0,0 +1,20 @@
+public class FindTheInsertionIndex {
+    public int findTheInsertionIndex(int[] nums, int target) {
+        int left = 0;
+        int right = nums.length;
+        while (left < right) {
+            int mid = (left + right) / 2;
+            // If the midpoint value is greater than or equal to the target, 
+            // the lower bound is either at the midpoint, or to its left.
+            if (nums[mid] >= target) {
+                right = mid;
+            }
+            // The midpoint value is less than the target, indicating the 
+            // lower bound is somewhere to the right.
+            else {
+                left = mid + 1;
+            }
+        }
+        return left;
+    }
+}