AcWing 第 16 场周赛

Author: EndlessCheng

misc/acwing/weekly/16/a/a.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"bufio"
+	. "fmt"
+	"io"
+	"os"
+	"strings"
+	"unicode"
+)
+
+// github.com/EndlessCheng/codeforces-go
+func run(_r io.Reader, _w io.Writer) {
+	in := bufio.NewReader(_r)
+	out := bufio.NewWriter(_w)
+	defer out.Flush()
+
+	var T int
+	var s string
+	for Fscan(in, &T); T > 0; T-- {
+		Fscan(in, &s)
+		low := 0
+		for _, b := range s {
+			if unicode.IsLower(b) {
+				low++
+			}
+		}
+		if low*2 < len(s) {
+			Fprintln(out, strings.ToUpper(s))
+		} else {
+			Fprintln(out, strings.ToLower(s))
+		}
+	}
+}
+
+func main() { run(os.Stdin, os.Stdout) }

misc/acwing/weekly/16/a/a_test.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"bufio"
+	. "fmt"
+	"io"
+	"os"
+)
+
+// github.com/EndlessCheng/codeforces-go
+func run(_r io.Reader, out io.Writer) {
+	in := bufio.NewReader(_r)
+	var n, v, cnt2, ans int
+	Fscan(in, &n)
+	if n < 3 {
+		Fprint(out, 0)
+		return
+	}
+
+	sum := make([]int, n+1)
+	for i := 0; i < n; i++ {
+		Fscan(in, &v)
+		sum[i+1] = sum[i] + v
+	}
+	if sum[n]%3 != 0 {
+		Fprint(out, 0)
+		return
+	}
+
+	avg := sum[n] / 3
+	for _, s := range sum[1:n] {
+		if s == avg*2 {
+			cnt2++
+		}
+	}
+
+	// 把等于 avg 的前缀和当成第一组，然后累加前缀和等于 avg*2 的前缀和的个数
+	for _, s := range sum[1:n] {
+		if s == avg*2 {
+			cnt2--
+		}
+		if s == avg {
+			ans += cnt2
+		}
+	}
+	Fprint(out, ans)
+}
+
+func main() { run(os.Stdin, os.Stdout) }

misc/acwing/weekly/16/b/b.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"bufio"
+	. "fmt"
+	"io"
+	"os"
+)
+
+// github.com/EndlessCheng/codeforces-go
+func run(_r io.Reader, out io.Writer) {
+	in := bufio.NewReader(_r)
+	var n int
+	Fscan(in, &n)
+	a := make([]int, n)
+	for i := range a {
+		Fscan(in, &a[i])
+	}
+	for i := 1; i < n-1; i++ {
+		if a[i] < a[i+1] && a[i] < a[0] || a[i] > a[i+1] && a[i] > a[0] {
+			Fprintln(out, 3)
+			Fprintln(out, 1, i+1, i+2)
+			return
+		}
+	}
+	Fprintln(out, 0)
+}
+
+func main() { run(os.Stdin, os.Stdout) }