Algorithms: Array Techniques Tutorials and Code Examples - Page 9

Next Lexicographic Permutation in C#

Next permutation advances a sequence to its immediate lexicographic successor, including sequences with duplicates..

csharp

    static int next_permutation(Span<int> a) {
        checked {
            int n = a.Length;
            alg_require(((n >= 0) && (n <= 1000000)));
            alg_require((a.Length == n));
            int pivot = (n - 2);
            int right = (n - 1);
            int left = 0;
            int temp = 0;
            int advanced = 0;
            while (((pivot >= 0) && (a[pivot] >= a[(pivot + 1)]))) {
                pivot = (pivot - 1);

Nov 15, 2026 csharp

Algorithms: Array Techniques

Next Lexicographic Permutation in PHP

Next permutation advances a sequence to its immediate lexicographic successor, including sequences with duplicates..

php

function next_permutation(array &$a): int {
    alg_require(array_is_list($a));
    $n = count($a);
    alg_require((($n >= 0) && ($n <= 1000000)));
    alg_require((count($a) == $n));
    $pivot = alg_sub($n, 2);
    $right = alg_sub($n, 1);
    $left = 0;
    $temp = 0;
    $advanced = 0;
    while ((($pivot >= 0) && ($a[$pivot] >= $a[alg_add($pivot, 1)]))) {
        $pivot = alg_sub($pivot, 1);

Nov 15, 2026 PHP

Algorithms: Array Techniques

Boyer Moore Majority Vote in C++

Majority vote cancels pairs of different values.

cpp

int majority_index(const std::vector<int>& a) {
    alg_require(a.size() <= 1000000);
    int n = (int)a.size();
    alg_require(((n >= 0) && (n <= 1000000)));
    alg_require(((int)a.size() == n));
    int candidate = 0;
    int balance = 0;
    int i = 0;
    int count = 0;
    while ((i < n)) {
        if ((balance == 0)) {
            candidate = i;

Nov 15, 2026 C++

Algorithms: Array Techniques

Boyer Moore Majority Vote in C#

Majority vote cancels pairs of different values.

csharp

    static int majority_index(ReadOnlySpan<int> a) {
        checked {
            int n = a.Length;
            alg_require(((n >= 0) && (n <= 1000000)));
            alg_require((a.Length == n));
            int candidate = 0;
            int balance = 0;
            int i = 0;
            int count = 0;
            while ((i < n)) {
                if ((balance == 0)) {
                    candidate = i;

Nov 15, 2026 csharp

Algorithms: Array Techniques

Two Pointer Pair Sum in PHP

Two pointers find whether two distinct positions in a sorted array sum to a target.

php

function pair_sum(array $a, int $target): int {
    alg_require(array_is_list($a));
    $n = count($a);
    alg_require((($n >= 0) && ($n <= 1000000)));
    alg_require((count($a) == $n));
    $left = 0;
    $right = alg_sub($n, 1);
    $total = 0;
    while (($left < $right)) {
        $total = alg_add($a[$left], $a[$right]);
        if (($total == $target)) {
            return 1;

Nov 15, 2026 PHP