From now on, I will add some topic wise problems which I face regularly. I think it will help new commers like me. Thank you :)

1.Cumulative sum/ prefix sum :

(https://codeforces.com/problemset/problem/363/B)

(https://codeforces.com/problemset/problem/313/B)

(https://codeforces.com/problemset/problem/1363/B)

(https://codeforces.com/problemset/problem/433/B)

(https://codeforces.com/problemset/problem/296/C)

(https://codeforces.com/problemset/problem/816/B)

(https://codeforces.com/problemset/problem/1341/B)

(https://codeforces.com/problemset/problem/961/B)

(https://codeforces.com/problemset/problem/276/C)

(https://codeforces.com/problemset/problem/1678/B1)

(https://codeforces.com/problemset/problem/1678/B1)

(https://www.spoj.com/problems/CSUMQ/en/)

(https://www.spoj.com/problems/RANGESUM/en/)

(https://www.codechef.com/problems/QUALPREL)

(https://www.codechef.com/problems/PTMSSNG)

(https://www.codechef.com/problems/MEX)

(https://www.codechef.com/problems/PTMSSNG)

(https://www.eolymp.com/en/problems/6959)

(https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=924)

Here are some Binary search related problems

2.Binary Search

(https://codeforces.com/problemset/problem/474/B)

(https://lightoj.com/problem/points-in-segments)

(https://lightoj.com/problem/counting-triangles)

(https://lightoj.com/problem/points-in-segments-ii)

(https://lightoj.com/problem/crossed-ladders)

(https://www.spoj.com/problems/EKO/)

(https://www.spoj.com/problems/PIE/)(https://www.spoj.com/problems/AGGRCOW/)

(https://www.codechef.com/problems/MINEAT)

(https://www.interviewbit.com/problems/painters-partition-problem/)

(https://codeforces.com/problemset/problem/230/B)

(https://codeforces.com/problemset/problem/474/B)

3. Even Odd integers counting in a range inclusive [l,r]:

Numbers of even integers is a range inclusive [l,r] = (r/2)-(l-1)/2

Numbers of odd integers is a range inclusive [l,r] = (r-l+1)-( (r/2)-(l-1)/2 ) Practice: https://codeforces.com/problemset/problem/1629/B

4. STL: MAP

(https://practice.geeksforgeeks.org/problems/find-the-frequency/1)

(https://practice.geeksforgeeks.org/problems/twice-counter4236/1)

(https://practice.geeksforgeeks.org/problems/word-with-maximum-frequency0120/1)

(https://atcoder.jp/contests/arc087/tasks/arc087_a)

(https://codeforces.com/contest/918/problem/B)

(https://www.spoj.com/problems/RPLD/)

(https://codeforces.com/contest/855/problem/A)

(https://codeforces.com/contest/4/problem/C)

(https://codeforces.com/contest/903/problem/C)

SET:

(https://codeforces.com/contest/558/problem/E)

(https://codeforces.com/problemset/problem/567/D)

(https://codeforces.com/contest/528/problem/A)

(https://codeforces.com/problemset/problem/22/A)

0 1 knapsack DP:

Dreamoon and WiFi Boredom

Topological Sort

B. Students and Shoelaces

Transitivity

Thank you :)