mirror of
https://github.com/krahets/hello-algo.git
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e720aa2d24
* Sync recent changes to the revised Word. * Revised the preface chapter * Revised the introduction chapter * Revised the computation complexity chapter * Revised the chapter data structure * Revised the chapter array and linked list * Revised the chapter stack and queue * Revised the chapter hashing * Revised the chapter tree * Revised the chapter heap * Revised the chapter graph * Revised the chapter searching * Reivised the sorting chapter * Revised the divide and conquer chapter * Revised the chapter backtacking * Revised the DP chapter * Revised the greedy chapter * Revised the appendix chapter * Revised the preface chapter doubly * Revised the figures
78 lines
1.9 KiB
Zig
78 lines
1.9 KiB
Zig
// File: iteration.zig
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// Created Time: 2023-09-27
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// Author: QiLOL (pikaqqpika@gmail.com)
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const std = @import("std");
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const Allocator = std.mem.Allocator;
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// for 循环
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fn forLoop(n: usize) i32 {
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var res: i32 = 0;
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// 循环求和 1, 2, ..., n-1, n
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for (1..n+1) |i| {
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res = res + @as(i32, @intCast(i));
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}
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return res;
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}
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// while 循环
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fn whileLoop(n: i32) i32 {
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var res: i32 = 0;
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var i: i32 = 1; // 初始化条件变量
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// 循环求和 1, 2, ..., n-1, n
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while (i <= n) {
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res += @intCast(i);
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i += 1;
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}
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return res;
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}
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// while 循环（两次更新）
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fn whileLoopII(n: i32) i32 {
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var res: i32 = 0;
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var i: i32 = 1; // 初始化条件变量
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// 循环求和 1, 4, 10, ...
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while (i <= n) {
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res += @intCast(i);
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// 更新条件变量
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i += 1;
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i *= 2;
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}
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return res;
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}
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// 双层 for 循环
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fn nestedForLoop(allocator: Allocator, n: usize) ![]const u8 {
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var res = std.ArrayList(u8).init(allocator);
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defer res.deinit();
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var buffer: [20]u8 = undefined;
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// 循环 i = 1, 2, ..., n-1, n
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for (1..n+1) |i| {
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// 循环 j = 1, 2, ..., n-1, n
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for (1..n+1) |j| {
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var _str = try std.fmt.bufPrint(&buffer, "({d}, {d}), ", .{i, j});
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try res.appendSlice(_str);
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}
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}
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return res.toOwnedSlice();
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}
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// Driver Code
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pub fn main() !void {
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const n: i32 = 5;
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var res: i32 = 0;
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res = forLoop(n);
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std.debug.print("\nfor 循环的求和结果 res = {}\n", .{res});
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res = whileLoop(n);
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std.debug.print("\nwhile 循环的求和结果 res = {}\n", .{res});
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res = whileLoopII(n);
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std.debug.print("\nwhile 循环（两次更新）求和结果 res = {}\n", .{res});
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const allocator = std.heap.page_allocator;
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const resStr = try nestedForLoop(allocator, n);
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std.debug.print("\n双层 for 循环的遍历结果 {s}\n", .{resStr});
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}
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