Introduction

Author: @wingkwong

Overview

Sorting refers to rearranging elements in a specific order. The most common order is either ascending or descending. There are a lot of algorithms to sort the array with different time complexity.

In C++, if define a static array of N elements of type int such as $a[4]$ you can sort like as below where $N$ is the number of elements to be sorted.

sort(a, a + N);

If you want to sort for a specific range $[x, y)$ , then use

sort(a + x, a + y);

For dynamic array, we do in such way

sort(a.begin(), a.end());

If you want to sort for a specific range $[x, y)$ , then use

sort(a.begin() + x, a.begin() + y);

To sort in an decreasing order,

sort(a.begin(), a.end(), greater<int>());

By default, sort() sorts the elements in the range $[x, y)$ into ascending order. If the container includes pairs, tuples or array<int, N>, it first sorts the first element, then the second element if there is a tie and so on. For example, the following comparator is same as sort(a.begin(), a.end());.

sort(a.begin(), a.end(), [&](const array<int, 3>& x, const array<int, 3>& y) {
    return (
        (x[0] < y[0]) || 
        (x[0] == y[0] && x[1] < y[1]) ||
        (x[0] == y[0] && x[1] == y[1] || x[2] < y[2])
    );
});

Overview​

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Overview