1. sort(arr,arr+n) : quick sort in (nlogn) ascending order.
2. sort(arr,arr+n,greater()) : sort in descending order.
3. sort(arr,arr+n, comparable) : sort accordingly.

	bool comparable(int a, int b)
	{
		return a>b;
	}

reverse(arr,arr+n);

*max_element(arr,arr+n);

*min_element(arr,arr+n);

accumulate(arr,arr+n,0) : 0 is to specify the initial value of sum

count(arr,arr+n);

find(arr,arr+n,pattern); return iterator to first match else vector.end() if not found

rotate(arr.begin(), arr.begin()+3, arr.end()); the element at 3rd position become the first after first rotate. rotate(arr.begin(), arr.end() + (arr.size() - 3), arr.end()); the element at 3rd position become the first after last 3rd rotate.

lower_bound(arr,arr+n,x);

upper_bound(arr,arr+n,x);

set_intersection(vec1.begin(),vect1.end(),vec2.begin(),vect2.end(), result.begin()) : store the common elements in result vector

set_union(vec1.begin(),vect1.end(),vec2.begin(),vect2.end(), result.begin()) : store the all elements in result vector

arr.erase(iteratorPosition) : erases the element at position +1 arr.erase(unique(arr.begin(),arr.end()), arr.end()) : erases the duplicate elements.

1. next_permutation(arr,arr+n);
2. prev_permutation(arr,arr+n);

1. str.find_last_of("pattern") :returns substring index position of the match from the last
2. str.find_first_of("pattern") : returns substring index position of the match from the beginning
3. str.find("pattern"): return position of the patterns first match else return -1;

3. str.substr(position) : return sub-string from that position to the last.
4. str.substr(indexPosition, substringLength) : return sub-string from that position to the sub-string length specified.

set<int,greater> setName; : stores element in descending order. set.insert(10);

set setName(arr.begin(),arr.end())

setName.find(30) : return iterator position else return setName.end()

1. setName.erase(value)
2. setName.erase(arr.begin(),arr.end(), setName.find(30) )

setName.count(element) : // return 1 if present or 0 when not present.

1. map<int,int> mapName;
2. mapName.insert(pair<int,int>(10,40));
3. itrPos->first : gives key
4. itrPos->second : gives value

mapName.find(keyValue)->second = newValue;