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const std = @import("std");
const testing = std.testing;
const mem = std.mem;
fn partition(comptime T: type, arr: []T, low: usize, high: usize) usize {
const pivot = arr[high];
var i: usize = low;
for (low..high) |j| {
if (arr[j] <= pivot) {
mem.swap(T, &arr[i], &arr[j]);
i += 1;
}
}
mem.swap(T, &arr[i], &arr[high]);
return i;
}
pub fn sort(comptime T: type, arr: []T, low: usize, high: usize) void {
if (low < high) {
const pivot_index = partition(T, arr, low, high);
if (pivot_index > low) {
sort(T, arr, low, pivot_index - 1);
}
sort(T, arr, pivot_index + 1, high);
}
}
test "quick sort" {
var arr = [_]i32{ 64, 34, 25, 12, 22, 11, 90 };
sort(i32, &arr, 0, arr.len - 1);
const expected = [_]i32{ 11, 12, 22, 25, 34, 64, 90 };
try testing.expectEqualSlices(i32, &expected, &arr);
}
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