Create Day 10 Find the Town Judge.cpp

Author: tusharjaiswal123

Day 10 Find the Town Judge.cpp

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+PROBLEM:
+
+
+In a town, there are N people labelled from 1 to N.  There is a rumor that one of these people is secretly the town judge.
+
+If the town judge exists, then:
+
+The town judge trusts nobody.
+Everybody (except for the town judge) trusts the town judge.
+There is exactly one person that satisfies properties 1 and 2.
+You are given trust, an array of pairs trust[i] = [a, b] representing that the person labelled a trusts the person labelled b.
+
+If the town judge exists and can be identified, return the label of the town judge.  Otherwise, return -1.
+
+ 
+
+Example 1:
+
+Input: N = 2, trust = [[1,2]]
+Output: 2
+Example 2:
+
+Input: N = 3, trust = [[1,3],[2,3]]
+Output: 3
+Example 3:
+
+Input: N = 3, trust = [[1,3],[2,3],[3,1]]
+Output: -1
+Example 4:
+
+Input: N = 3, trust = [[1,2],[2,3]]
+Output: -1
+Example 5:
+
+Input: N = 4, trust = [[1,3],[1,4],[2,3],[2,4],[4,3]]
+Output: 3
+
+
+
+SOLUTION:
+
+class Solution {
+public:
+    int findJudge(int N, vector<vector<int>>& trust) {
+        
+        unordered_map<int,int> m;
+        int i,j,n,ans=-1,k;
+        n=trust.size();
+        
+        for(i=0;i<n;i++)
+        {
+            m[trust[i][1]]++;
+        }
+        
+        for(i=1;i<=N;i++)
+        {
+            if(m[i]==N-1 && ans==-1)
+            {
+                ans=i;
+                break;
+            }
+            
+        }
+        
+        if(ans!=-1)
+        {
+            for(i=0;i<n;i++)
+            {
+                if(trust[i][0]==ans)
+                {
+                    ans=-1;
+                    break;
+                }
+            }
+        }     
+        
+        return ans;
+    }
+};