Codeforces 416A Guess a number!

416A Guess a number!.cpp

//This program is for Codeforces 416A Guess a number!
//題目來源 Problem link: http://codeforces.com/problemset/problem/416/A

/** my mistakes from code on paper

compiler errers:
1. reduceRange(char[] oper) --> reduceRange (char* oper)
2. char[] reverseOper(char op) --> char* reverseOper(char* op)
3. declare function reverseOper after the function reduceRange

problem-solving logic: right
*/

#include<stdio.h>
#include<string.h>

char* reverseOper(char* op)
{
    if(strcmp(op, "<") == 0)
        return ">=";
    if(strcmp(op, "<=") == 0)
        return ">";
    if(strcmp(op, ">") == 0)
        return "<=";
    if(strcmp(op, ">=") == 0)
        return "<";
}


void reduceRange(char* oper, int num, char ans, int& Max, int& Min)
{
    if(ans == 'N')
        oper = reverseOper(oper);

    if(strcmp(oper, "<") == 0){
        if(Max > (num - 1))
            Max = (num - 1);
    }
    else if(strcmp(oper, "<=") == 0){
        if(Max > num)
            Max = num;
    }
    else if(strcmp(oper, ">") == 0){
        if(Min < (num + 1))
            Min = (num + 1);
    }
    else if(strcmp(oper, ">=") == 0){
        if(Min < num)
            Min = num;
    }
}

int main()
{
    int n, Max, Min, num;
    char oper[3], ans;

    while(scanf("%d", &n) != EOF)
    {
        Max = 2e9;
        Min = -2e9;

        while(n--)
        {
            scanf("%s %d %c", &oper, &num, &ans);
            reduceRange(oper, num, ans, Max, Min);
        }

        //printf("%d\t%d\n", Min, Max);

        if(Min > Max)
            printf("Impossible\n");
        else
            printf("%d\n", Min);
    }
    return 0;
}

416A Guess a number_code on paper.cpp

//This program is for Codeforces 416A Guess a number! (code on paper)
//題目來源 Problem link: http://codeforces.com/problemset/problem/416/A
//it's wrong and can't compile


#include<stdio.h>
#include<string.h>

void reduceRange(char[] oper, int num, char ans, int& Max, int& Min)
{
    if(ans == 'N')
        oper = reverseOper(oper);

    if(strcmp(oper, "<") == 0){
        if(Max > (num - 1))
            Max = (num - 1);
    }
    else if(strcmp(oper, "<=") == 0){
        if(Max > num)
            Max = num;
    }
    else if(strcmp(oper, ">") == 0){
        if(Min < (num + 1))
            Min = (num + 1);
    }
    else if(strcmp(oper, ">=") == 0){
        if(Min < num)
            Min = num;
    }
}

char[] reverseOper(char op)
{
    if(strcmp(op, "<") == 0)
        return ">=";
    if(strcmp(op, "<=") == 0)
        return ">";
    if(strcmp(op, ">") == 0)
        return "<=";
    if(strcmp(op, ">=") == 0)
        return "<";
}

int main()
{
    int n, Max, Min, num;
    char oper[3], ans;

    while(scanf("%d", &n) != EOD)
    {
        Max = 2e9;
        Min = -2e9;

        while(n--)
        {
            scanf("%s %d %c", &oper, &num, &ans);
            reduceRange(oper, num, ans, Max, Min);
        }
        if(Min > Max)
            printf("Impossible\n");
        else
            printf("%d\n", Min);
    }
    return 0;
}