fd

Author: dingjikerbo

solution/src/main/java/com/inuker/solution/MinimumSizeSubarraySum.java

@@ -1,5 +1,7 @@
 package com.inuker.solution;
 
+import java.util.Arrays;
+
 /**
  * Created by dingjikerbo on 16/11/22.
  */
@@ -14,7 +16,7 @@ public int minSubArrayLen(int s, int[] nums) {
              * 这里别掉了等号
              */
             if (sum >= s) {
-                for ( ; j < i; j++) {
+                for (; j < i; j++) {
                     if (sum - nums[j] < s) {
                         break;
                     }
@@ -25,4 +27,26 @@ public int minSubArrayLen(int s, int[] nums) {
         }
         return min == Integer.MAX_VALUE ? 0 : min;
     }
+
+    /**
+     * O(nlgn)的写法
+     * sums[0]必须是0，TestCase[1,2,3,4,5],15
+     */
+    public int minSubArrayLen2(int s, int[] nums) {
+        int[] sums = new int[nums.length + 1];
+        for (int i = 0; i < nums.length; i++) {
+            sums[i + 1] = nums[i] + sums[i];
+        }
+        int minLen = Integer.MAX_VALUE;
+        for (int i = 0; i < sums.length; i++) {
+            int end = Arrays.binarySearch(sums, i + 1, sums.length, sums[i] + s);
+            end = end < 0 ? -(end + 1) : end;
+            if (end == sums.length) {
+                break;
+            }
+            minLen = Math.min(end - i, minLen);
+        }
+        return minLen == Integer.MAX_VALUE ? 0 : minLen;
+    }
+
 }

test/src/main/java/com/inuker/test/main.java

@@ -1,5 +1,6 @@
 package com.inuker.test;
 
+import com.inuker.solution.MinimumSizeSubarraySum;
 import com.inuker.solution.NextPermutation;
 import com.inuker.solution.SearchForARange;
 import com.leetcode.library.ListNode;
@@ -30,31 +31,9 @@ public class main {
 
     public static void main(String[] args) {
         int[] arr = new int[]{
-                2, 2, 0, 4, 3, 1
+                1, 2, 3, 4, 5
         };
-        new NextPermutation().nextPermutation(arr);
-        for (int n : arr) {
-            System.out.print(n + " ");
-        }
-    }
-
-    public boolean searchMatrix(int[][] matrix, int target) {
-        if (matrix.length == 0) {
-            return false;
-        }
-        int row = matrix.length, col = matrix[0].length;
-        int left = 0, right = row * col - 1;
-        while (left <= right) {
-            int mid = (left + right) / 2;
-            int x = mid / col, y = mid % col;
-            if (target == matrix[x][y]) {
-                return true;
-            } else if (target > matrix[x][y]) {
-                left = mid + 1;
-            } else {
-                right = mid - 1;
-            }
-        }
-        return false;
+        int len = new MinimumSizeSubarraySum().minSubArrayLen2(15, arr);
+        System.out.println(len);
     }
 }