judge6-1.c

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

int match(int x, char s[]) {
    int i = strlen(s)-1;
    for ( ; i >= 0; i-- ) {
        if ( s[i] == '?' ) {
            x /= 10;
            continue;
        }
        if ( s[i] - '0' != x % 10 ) return 0;
        x /= 10;
    }
    return 1;
}

int main() {
    char a[3][20];
    
    scanf("%s %s %s", &a[0], &a[1], &a[2]);
    int length[3] = {strlen(a[0]), strlen(a[1]), strlen(a[2])};
    int min[3], max[3];
    int i, j, k, digit;
    for ( i = 0; i < 3; i++ ) {
        min[i] = max[i] = 0;
    }
    for ( j = 0; j < 2; j++ ) {
        digit = 1;
        for ( i = length[j]-1; i >= 0; i-- ) {
            if ( a[j][i] == '?' ) {
                min[j] += (0 * digit);
                max[j] += (9 * digit);
            } else {
                min[j] += (a[j][i] - '0') * digit;
                max[j] += (a[j][i] - '0') * digit;
            }
            digit *= 10;
        }
    }
    for ( i = min[0]; i <= max[0]; i++ ) {
        for ( j = min[1]; j <= max[1]; j++ ) {
            if ( match( i, a[0] ) && match( j, a[1] ) && match( i+j, a[2] ) )
                printf( "%d + %d = %d\n", i, j, i+j );
        }
    }
    return 0;
}