英文:
Prime generator program SPOJ wrong answer
问题
问题描述
> 输入
>
> 输入以单行中的测试用例数 t 开始(t<=10)。在接下来的 t 行中,有两个数字 m 和 n(1 <= m <= n <= 1000000000,n-m<=100000),用空格分隔。
>
> 输出
>
> 对于每个测试用例,打印所有满足 m <= p <= n 的素数 p,每行一个数字,用空行分隔测试用例。
>
> 示例
>
> 输入:
>
> 2
> 1 10
> 3 5
>
> 输出:
>
> 2
> 3
> 5
> 7
>
> 3
> 5
我的问题
我尝试用 golang
编写这个问题,一开始我遇到了超时错误,然后我通过找到最大的 n
并且只生成一次素数来解决了这个问题。但是现在我遇到了错误答案。有人可以帮我找到错误吗?我无法弄清楚。谢谢。
package main
import (
"fmt"
"math"
)
func main() {
var k, j, i, max_m, max_n, test_cases, kase int64
fmt.Scanln(&test_cases)
case_m, case_n := make([]int64, test_cases), make([]int64, test_cases)
EratosthenesArray := make(map[int64][]bool)
max_m = 0
max_n = 0
for i = 0; i < test_cases; i++ {
fmt.Scanf("%d %d", &case_m[i], &case_n[i])
if case_m[i] > case_n[i] {
case_m[i] = 0
case_n[i] = 0
}
if max_m < case_m[i] {
max_m = case_m[i]
}
if max_n < case_n[i] {
max_n = case_n[i]
}
length := case_n[i] - case_m[i] + 1
EratosthenesArray[i] = make([]bool, length)
}
if max_m <= max_n {
upperbound := int64(math.Sqrt(float64(max_n)))
UpperboundArray := make([]bool, upperbound+1)
for i = 2; i <= upperbound; i++ {
if !UpperboundArray[i] {
for k = i * i; k <= upperbound; k += i {
UpperboundArray[k] = true
}
for kase = 0; kase < test_cases; kase++ {
start := (case_m[kase] - i*i) / i
if case_m[kase]-i*i < 0 {
start = i
}
for k = start * i; k <= case_n[kase]; k += i {
if k >= case_m[kase] && k <= case_n[kase] {
EratosthenesArray[kase][k-case_m[kase]] = true
}
}
}
}
}
}
for i = 0; i < test_cases; i++ {
k = 0
for j = 0; j < case_n[i]-case_m[i]; j++ {
if !EratosthenesArray[i][j] {
ret := case_m[i] + j
if ret > 1 {
fmt.Println(ret)
}
}
}
fmt.Println()
}
}
英文:
Problem Statement
> Input
>
> The input begins with the number t of test cases in a single line
> (t<=10). In each of the next t lines there are two numbers m and n (1
> <= m <= n <= 1000000000, n-m<=100000) separated by a space.
>
> Output
>
> For every test case print all prime numbers p such that m <= p <= n,
> one number per line, test cases separated by an empty line.
>
> Example
>
> Input:
>
> 2
> 1 10
> 3 5
>
> Output:
>
> 2
> 3
> 5
> 7
>
> 3
> 5
My Problem
I have tried to write this problem with golang
, at beginning I got time limit exceed error, then I solved it with finding the biggest n
and only generate prime once. But now I got wrong answer error. Anyone can help to to find the bug? I can't figure it out. Thanks.
package main
import (
"fmt"
"math"
)
func main() {
var k, j, i, max_m, max_n, test_cases, kase int64
fmt.Scanln(&test_cases)
case_m, case_n := make([]int64, test_cases), make([]int64, test_cases)
EratosthenesArray := make(map[int64][]bool)
max_m = 0
max_n = 0
for i = 0; i < test_cases; i++ {
fmt.Scanf("%d %d", &case_m[i], &case_n[i])
if case_m[i] > case_n[i] {
case_m[i] = 0
case_n[i] = 0
}
if max_m < case_m[i] {
max_m = case_m[i]
}
if max_n < case_n[i] {
max_n = case_n[i]
}
length := case_n[i] - case_m[i] + 1
EratosthenesArray[i] = make([]bool, length)
}
if max_m <= max_n {
upperbound := int64(math.Sqrt(float64(max_n)))
UpperboundArray := make([]bool, upperbound+1)
for i = 2; i <= upperbound; i++ {
if !UpperboundArray[i] {
for k = i * i; k <= upperbound; k += i {
UpperboundArray[k] = true
}
for kase = 0; kase < test_cases; kase++ {
start := (case_m[kase] - i*i) / i
if case_m[kase]-i*i < 0 {
start = i
}
for k = start * i; k <= case_n[kase]; k += i {
if k >= case_m[kase] && k <= case_n[kase] {
EratosthenesArray[kase][k-case_m[kase]] = true
}
}
}
}
}
}
for i = 0; i < test_cases; i++ {
k = 0
for j = 0; j < case_n[i]-case_m[i]; j++ {
if !EratosthenesArray[i][j] {
ret := case_m[i] + j
if ret > 1 {
fmt.Println(ret)
}
}
}
fmt.Println()
}
}
答案1
得分: 1
根据评论,每个质数范围的输出总是少一行,所以这是一个被接受的解决方案。
package main
import (
"fmt"
"math"
)
func main() {
var k, j, i, max_m, max_n, test_cases, kase int64
fmt.Scanln(&test_cases)
case_m, case_n := make([]int64, test_cases), make([]int64, test_cases)
EratosthenesArray := make(map[int64][]bool)
max_m = 0
max_n = 0
for i = 0; i < test_cases; i++ {
fmt.Scanf("%d %d", &case_m[i], &case_n[i])
if case_m[i] > case_n[i] {
case_m[i] = 0
case_n[i] = 0
}
if max_m < case_m[i] {
max_m = case_m[i]
}
if max_n < case_n[i] {
max_n = case_n[i]
}
length := case_n[i] - case_m[i] + 1
EratosthenesArray[i] = make([]bool, length)
}
if max_m <= max_n {
upperbound := int64(math.Sqrt(float64(max_n)))
UpperboundArray := make([]bool, upperbound+1)
for i = 2; i <= upperbound; i++ {
if !UpperboundArray[i] {
for k = i * i; k <= upperbound; k += i {
UpperboundArray[k] = true
}
for kase = 0; kase < test_cases; kase++ {
start := (case_m[kase] - i*i) / i
if case_m[kase]-i*i < 0 {
start = i
}
for k = start * i; k <= case_n[kase]; k += i {
if k >= case_m[kase] && k <= case_n[kase] {
EratosthenesArray[kase][k-case_m[kase]] = true
}
}
}
}
}
}
for i = 0; i < test_cases; i++ {
k = 0
for j = 0; j <= case_n[i]-case_m[i]; j++ {
if !EratosthenesArray[i][j] {
ret := case_m[i] + j
if ret > 1 {
fmt.Println(ret)
}
}
}
fmt.Println()
}
}
请注意,我只更改了一行代码,将 for j = 0; j < case_n[i]-case_m[i]; j++ {
改为 for j = 0; j <= case_n[i]-case_m[i]; j++ {
。
执行时间约为1.08秒,内存约为772M(但似乎golang在spoj中的初始内存为771M,所以实际内存使用可能为1M)。
英文:
according to the comments, the output for each prime number range is always have one line short, so here is the ACCEPTED solution
package main
import (
"fmt"
"math"
)
func main() {
var k, j, i, max_m, max_n, test_cases, kase int64
fmt.Scanln(&test_cases)
case_m, case_n := make([]int64, test_cases), make([]int64, test_cases)
EratosthenesArray := make(map[int64][]bool)
max_m = 0
max_n = 0
for i = 0; i < test_cases; i++ {
fmt.Scanf("%d %d", &case_m[i], &case_n[i])
if case_m[i] > case_n[i] {
case_m[i] = 0
case_n[i] = 0
}
if max_m < case_m[i] {
max_m = case_m[i]
}
if max_n < case_n[i] {
max_n = case_n[i]
}
length := case_n[i] - case_m[i] + 1
EratosthenesArray[i] = make([]bool, length)
}
if max_m <= max_n {
upperbound := int64(math.Sqrt(float64(max_n)))
UpperboundArray := make([]bool, upperbound+1)
for i = 2; i <= upperbound; i++ {
if !UpperboundArray[i] {
for k = i * i; k <= upperbound; k += i {
UpperboundArray[k] = true
}
for kase = 0; kase < test_cases; kase++ {
start := (case_m[kase] - i*i) / i
if case_m[kase]-i*i < 0 {
start = i
}
for k = start * i; k <= case_n[kase]; k += i {
if k >= case_m[kase] && k <= case_n[kase] {
EratosthenesArray[kase][k-case_m[kase]] = true
}
}
}
}
}
}
for i = 0; i < test_cases; i++ {
k = 0
for j = 0; j <= case_n[i]-case_m[i]; j++ {
if !EratosthenesArray[i][j] {
ret := case_m[i] + j
if ret > 1 {
fmt.Println(ret)
}
}
}
fmt.Println()
}
}
Note that I only changed one line from for j = 0; j < case_n[i]-case_m[i]; j++ {
to for j = 0; j <= case_n[i]-case_m[i]; j++ {
And the execution time is about 1.08s, memory is about 772M (but seems the initial memory for golang in spoj is 771M, so it might be about 1M memory usage)
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