题目链接：http://acm.sgu.ru/problem.php?contest=0&problem=546
这题还好，１Ｙ，考虑情况周全，就没问题了，还好提交之前把想到的情况都测试了一遍．．
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
char s[];
int n, a, b, a0[], b0[];
int main(void) {
//freopen("in.txt", "r", stdin);
while (~scanf("%d%d%d%s", &n, &a, &b, s)) {
int a1 = , b1 = ;
for (int i = ;i < n; ++i) {
if (s[i] == '') a0[a1] = i, a1++; else if (s[i] == '') b0[b1] = i, b1++;
}
if (a1 == a && b1 == b) printf("0\n%s\n", s);
else if (a+b>n) printf("-1\n");
else {
int cnt = , a2 = , b2 = ;
a2 = a1-a, b2 = b1-b;
if (a1 < a) {
for (int f = ; f < b2 && a1 < a; ++f) s[b0[f]] = '', cnt++, a1++, b1--;
if (a1 < a) {
for (int e = ; e < n && a1 < a; ++e) if (s[e] == '') s[e] = '', cnt++, a1++;
}
}
if (b1 < b) {
for (int f = ; f < a2 && b1 < b; ++f) s[a0[f]] = '', cnt++, b1++, a1--;
if (b1 < b) {
for (int e = ; e < n && b1<b; ++e) if (s[e] == '') s[e] = '', cnt++, b1++;
}
}
if (a1 > a) {
for (int f = ; f < n && a1 > a; ++f) if (s[f] == '') a1--, s[f] = '', cnt++;
}
if (b1 > b) {
for (int f = ; f < n && b1 > b; ++f) if (s[f] == '') b1--, s[f] = '', cnt++;
}
printf("%d\n%s\n", cnt, s);
}
} return ;
}
只是我的方法貌似比较笨＝＝