poj-3225.c

#include <stdio.h>
#include <stdbool.h>

#define MAXINST 65536   // max instructions
#define AXISLEN 0x1FFFF

bool axis[AXISLEN];     // 2 * 0x10000 - 1

void actU(int left, int right) {
    // S ← S ∪ T
    int i;
    for(i=left; i<=right; i++)
        axis[i] = 1;
}
void actI(int left, int right) {
    // S ← S ∩ T
    int i;
    for(i=0; i<left; i++)
        axis[i] = 0;
    for(i=right+1; i<AXISLEN; i++)
        axis[i] = 0;
}
void actD(int left, int right) {
    // S ← S − T
    int i;
    for(i=left; i<=right; i++)
        axis[i] = 0;
}
void actC(int left, int right) {
    // S ← T − S
    int i;
    actI(left, right);
    for(i=left; i<=right; i++)
        axis[i] = !axis[i];
}
void actS(int left, int right) {
    // S ← S ⊕ T
    int i;
    for(i=left; i<=right; i++)
        axis[i] = !axis[i];
}

int main()
{
    char act, sign_left, sign_right;
    int left, right;
    while(
        scanf("%c %c%d,%d%c%*c", &act, &sign_left, &left, &right, &sign_right) != EOF
    ) {
        // Input
        left *=2;
        right*=2;
        if(sign_left =='(') left++;
        if(sign_right==')') right--;
        
        // Process
        switch(act) {
            case 'U':
                actU(left, right); break;
            case 'I':
                actI(left, right); break;
            case 'D':
                actD(left, right); break;
            case 'C':
                actC(left, right); break;
            case 'S':
                actS(left, right); break;
        }
    }
    
    // Output
    int i;
    bool isEmpty;
    isEmpty=1;
    
    for(i=0; i<AXISLEN; i++)
        if(axis[i]) {
            left=i; // the left 1
            i++;    // Loop from next one.
            while(axis[i]) i++;
            right=i-1;  // the Right 1;
            
            if(!isEmpty) printf(" ");
            isEmpty=0;
            if(left & 1)    // odd number
                printf("(%d,", left/2); // 3 => (1
            else            // even number
                printf("[%d,", left/2); // 4 => [2
            if(right & 1)
                printf("%d)", right/2+1);   // 3 => 2)
            else
                printf("%d]", right/2); // 4 => 2]
        }
    if(isEmpty)
        printf("empty set");
    printf("\n");
    
    return 0;
}