maximum size subarray sum equals k

fishercoder1534 · fishercoder1534 · commit 8466382d8def · 2016-08-25T13:19:10.000-07:00
diff --git a/MEDIUM/src/medium/MaximumSizeSubarraySumEqualsK.java b/MEDIUM/src/medium/MaximumSizeSubarraySumEqualsK.java
@@ -0,0 +1,47 @@
+package medium;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import utils.CommonUtils;
+
+public class MaximumSizeSubarraySumEqualsK {
+    public int maxSubArrayLen_On_solution(int[] nums, int k) {
+        Map<Integer, Integer> map = new HashMap();
+        int sum = 0, max = 0;
+        for(int i = 0; i < nums.length; i++){
+            sum += nums[i];
+            if(sum == k) max = i+1;
+            else if(map.containsKey(sum-k)) max = Math.max(max, i-map.get(sum-k));
+            if(!map.containsKey(sum)) map.put(sum, i);
+        }
+        return max;
+    }
+
+    
+    public static int maxSubArrayLen_On2_solution(int[] nums, int k) {
+        //NOTES: didn't finish this one
+        int[] sums = new int[nums.length];
+        int max = 0;
+        for(int i = 0; i < nums.length; i++){
+            if(i == 0) sums[i] = nums[i];
+            else sums[i] = sums[i-1] + nums[i];
+            if(sums[i] == k) max = i+1;//then this one must be the max
+        }
+        CommonUtils.printArray(sums);
+        //do computation for each possible subarray of sums and find the max length
+        return max;
+    }
+    
+    public static void main(String...args){
+        //correct answer is 4
+//        int[] nums = new int[]{1, -1, 5, -2, 3};
+//        int k = 3;
+        
+        //correct answer is 2
+        int[] nums = new int[]{-2, -1, 2, 1};
+        int k = 1;
+        maxSubArrayLen_On2_solution(nums, k);
+    }
+    
+}
