From e517dd9059bd568ce41dfd7e3820a9305de789b0 Mon Sep 17 00:00:00 2001
From: kbkpbot <kbkpbot@sina.com>
Date: Sun, 4 Jan 2026 15:55:30 +0800
Subject: [PATCH] bench: add benchmark for string dedup (#26254)

---
 bench/bench_string_dedup.v | 121 +++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 bench/bench_string_dedup.v

diff --git a/bench/bench_string_dedup.v b/bench/bench_string_dedup.v
new file mode 100644
index 000000000..72ccd237b
--- /dev/null
+++ b/bench/bench_string_dedup.v
@@ -0,0 +1,121 @@
+// Benchmark comparison of four string deduplication methods in V: basic array, pre-allocated array, map, and set
+module main
+
+import time
+import datatypes
+
+// Method 1: Using basic array (no pre-allocation)
+struct Context1 {
+mut:
+	used_str []string
+}
+
+fn (mut c Context1) add_used(str string) {
+	if str !in c.used_str {
+		c.used_str << str
+	}
+}
+
+// Method 2: Using pre-allocated array with capacity
+struct Context2 {
+mut:
+	used_str []string
+}
+
+fn (mut c Context2) add_used(str string) {
+	if str !in c.used_str {
+		c.used_str << str
+	}
+}
+
+// Method 3: Using map
+struct Context3 {
+mut:
+	used_str map[string]bool
+}
+
+fn (mut c Context3) add_used(str string) {
+	c.used_str[str] = true
+}
+
+// Method 4: Using set
+struct Context4 {
+mut:
+	used_str datatypes.Set[string]
+}
+
+fn (mut c Context4) add_used(str string) {
+	c.used_str.add(str)
+}
+
+// Generate random test strings
+fn generate_test_strings(count int, duplicate_ratio f64) []string {
+	mut strs := []string{cap: count}
+	unique_count := int(f64(count) * (1.0 - duplicate_ratio))
+	// First generate a batch of unique strings
+	for i in 0 .. unique_count {
+		strs << 'str_${i}_${time.ticks()}' // Add timestamp to reduce duplication rate
+	}
+	// The remaining part uses duplicate strings
+	for i in 0 .. (count - unique_count) {
+		strs << strs[i % unique_count] // Cycle through the first half of strings to create duplicates
+	}
+	return strs
+}
+
+fn main() {
+	num_strs := 10000 // Total number of strings
+	duplicate_ratio := 0.3 // Duplicate string ratio (30%)
+	test_strs := generate_test_strings(num_strs, duplicate_ratio)
+	println('Generated test strings: ${test_strs.len} (approximately ${int(duplicate_ratio * 100)}% are duplicates)')
+
+	// Test method 1: basic array (no pre-allocation)
+	mut ctx1 := Context1{}
+	sw1 := time.new_stopwatch()
+	for str in test_strs {
+		ctx1.add_used(str)
+	}
+	time1 := sw1.elapsed().milliseconds()
+	println('Method 1 (basic array) - Time: ${time1}ms, Final unique strings: ${ctx1.used_str.len}')
+
+	// Test method 2: pre-allocated array
+	mut ctx2 := Context2{
+		used_str: []string{cap: num_strs} // Pre-allocate capacity to avoid reallocations
+	}
+	sw2 := time.new_stopwatch()
+	for str in test_strs {
+		ctx2.add_used(str)
+	}
+	time2 := sw2.elapsed().milliseconds()
+	println('Method 2 (pre-allocated array) - Time: ${time2}ms, Final unique strings: ${ctx2.used_str.len}')
+
+	// Test method 3: map
+	mut ctx3 := Context3{}
+	sw3 := time.new_stopwatch()
+	for str in test_strs {
+		ctx3.add_used(str)
+	}
+	time3 := sw3.elapsed().milliseconds()
+	println('Method 3 (map) - Time: ${time3}ms, Final unique strings: ${ctx3.used_str.len}')
+
+	// Test method 4: set
+	mut ctx4 := Context4{}
+	sw4 := time.new_stopwatch()
+	for str in test_strs {
+		ctx4.add_used(str)
+	}
+	time4 := sw4.elapsed().milliseconds()
+	println('Method 4 (set) - Time: ${time4}ms, Final unique strings: ${ctx4.used_str.size()}')
+
+	// Performance comparison
+	println('\nPerformance comparison:')
+	println('Method 2 (pre-allocated array) is ${f64(time1) / f64(time2):.2f} times faster than method 1 (basic array)')
+	println('Method 3 (map) is ${f64(time1) / f64(time3):.2f} times faster than method 1 (basic array)')
+	println('Method 4 (set) is ${f64(time1) / f64(time4):.2f} times faster than method 1 (basic array)')
+
+	if time3 < time4 {
+		println('Map is slightly faster than set, difference: ${time4 - time3}ms')
+	} else {
+		println('Set is slightly faster than map, difference: ${time3 - time4}ms')
+	}
+}
-- 
2.39.5