Add solution for Day 04 problem in day04sol2.cpp

Problems/Data-structures/Day-04/sol/Sujal_Kshatri/day04sol2.cpp

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+//submission link - https://codeforces.com/problemset/submission/1912/355802995
+
+/*
+Approach:
+
+We start with a number `num`.
+
+From each list, we take numbers from left to right.
+If numbers go down first but later go up, we save that part as a "good chunk".
+
+For every good chunk, we remember:
+-how much `num` we need to start it
+- how much `num` increases after it
+
+Then we sort all chunks by how much `num` they need.
+We take chunks one by one if we can afford them.
+
+This way, `num` grows as much as possible.
+*/
+
+#include<bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+	long long num,k;
+	cin >> num >> k;
+	long long i,j;
+	vector<pair<long long,long long>> v;
+	for(i=0;i<k;i++)
+	{
+		long long n;
+		cin >> n;
+		long long maxi=0,add=0;
+		for(j=0;j<n;j++)
+		{
+			long long x;
+			cin >> x;
+			add += x;
+			maxi = max(maxi,-add);
+			if(add>0)
+			{
+				v.push_back({maxi,add});
+				add=0;
+			}
+		}
+	}
+	sort(v.begin(),v.end());
+	for(auto x:v)
+	{
+		if(x.first>num) 
+		break;
+		num += x.second;
+	}
+	cout << num << endl;
+	return 0;
+}