Updated

Author: codewithdev

21- Hashing/longestSubarraywithSumK.cpp

@@ -0,0 +1,36 @@
+#include<bits/stdc++.h>
+using namespace std;
+int checkIfSubarraySumZero(int *arr, int n,int k){
+	unordered_map<int,int>mp;
+    int pre=0;
+    int len=0;
+    for(int i=0;i<n;i++){
+    	pre+= arr[i];
+    	if(pre==k){
+    		len= max(len,i+1);
+    	}
+    	if(mp.find(pre-k)!=mp.end()){
+    		len= max(len,i-mp[pre-k]);
+    	}
+    	else{
+    		mp[pre-k]=i;
+    	}
+    }
+    return len;
+}
+
+int main(){
+
+	int n;
+	cin>>n;
+	int k;
+	cin>>k;
+	int *arr= new int[n];
+	for(int i=0;i<n;i++){
+		cin>>arr[i];
+	}
+	int b= checkIfSubarraySumZero(arr,n,k);
+	cout<<b<<endl;
+	return 0;
+
+}