05 August 2008
给两个整数a和b，造一个字符串里面刚好有a个a和b个b，但不会出现连续三次的aaa或bbb，返回任意一个结果
Greedy
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public String strWithout3a3b(int A, int B) {
StringBuilder res = new StringBuilder(A + B);
char a = 'a', b = 'b';
int i = A, j = B;
if (B > A) { a = 'b'; b = 'a'; i = B; j = A; }
while (i-- > 0) {
res.append(a);
if (i > j) { res.append(a); --i; }
if (j-- > 0) res.append(b);
}
return res.toString();
}
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string strWithout3a3b(int A, int B, char a = 'a', char b = 'b') {
if (B > A) return strWithout3a3b(B, A, b, a);
if (B == 0) return string(A, a);
return string(A > B ? 2 : 1, a) + b + strWithout3a3b(A - (A > B ? 2 : 1), B - 1, a, b);
}