Submission #1977756

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Source Code Expand

package main

import (
	"bufio"
	"fmt"
	_ "math"
	"os"
	_ "sort"
)

func Min64(x, y int64) int64 {
	if x < y {
		return x
	}
	return y
}

func Max64(x, y int64) int64 {
	if x > y {
		return x
	}
	return y
}

var reader *bufio.Reader = bufio.NewReader(os.Stdin)
var writer *bufio.Writer = bufio.NewWriter(os.Stdout)

func printf(f string, a ...interface{}) { fmt.Fprintf(writer, f, a...) }
func println(a ...interface{})          { fmt.Fprintln(writer, a...) }
func scanf(f string, a ...interface{})  { fmt.Fscanf(reader, f, a...) }
func scanln(a ...interface{})           { fmt.Fscanln(reader, a...) }

func main() {
	defer writer.Flush()

	var x, l, r int64
	scanln(&x)
	l = -1
	r = 10e9
	for l+1 < r {
		// println(l, r)
		m := (l + r) / 2
		y := m * (m + 1) / 2
		if y >= x {
			r = m
		} else {
			l = m
		}
	}

	println(r)
}

Submission Info

Judge Result