56 lines
1.5 KiB
C++
56 lines
1.5 KiB
C++
#include <stdio.h>
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#include <string.h>
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const int N = 1005;
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char str[N];
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int n, pos[N], num, len, cnt;
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bool judge() {
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for (int i = 0, j = len - 1; i < len; i++, j--)
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if (str[i] != str[j])
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return false;
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return true;
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}
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int main() {
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while (scanf("%d", &n) == 1) {
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scanf("%s", str);
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num = 0;
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len = strlen(str);
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for (int i = 0; i < len; i++) {
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if (str[i] == '?') {
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str[i] = 'a';
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pos[num++] = i;
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}
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}
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if (num == 0 && !judge()) {
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printf("%s\n", str);
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continue;
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}
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if (num == 0 && judge() || len == 1) {
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printf("QwQ\n");
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continue;
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}
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if (len & 1) {
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if (!judge()) {
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printf("%s\n", str);
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continue;
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}
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bool flag = judge();
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if (flag && pos[num - 1] != len / 2) {
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str[pos[num - 1]] = 'b';
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printf("%s\n", str);
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}
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else if (flag && pos[num - 1] == len / 2 && num == 1)
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printf("QwQ\n");
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else if (flag && pos[num - 1] == len / 2 && num > 1) {
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str[pos[num - 2]] = 'b';
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printf("%s\n", str);
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}
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}
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else {
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if (judge())
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str[pos[num - 1]] = 'b';
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printf("%s\n", str);
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}
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}
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return 0;
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}
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