LeetCode.1189-balloon实例数最大值(Maximum Number of Balloons)

看题和准备

• 1 <= text.length <= 10^4
• 文本字符串仅包含小写英文字母。

第一种解法

``````public int maxNumberOfBalloons(String text) {
if (text == "" || text.length() < 7) {
return 0;
}
int A = 0, B = 0, L = 0, O = 0, N = 0;
int len = text.length();
for (int i=0; i<len; i++) {
if (text.charAt(i) == 'a') {
A++;
} else if (text.charAt(i) == 'b') {
B++;
} else if (text.charAt(i) == 'l') {
L++;
} else if (text.charAt(i) == 'n') {
N++;
} else if (text.charAt(i) == 'o') {
O++;
}
}
L /= 2;
O /= 2;
int min = Math.min(A, B);
min = Math.min(min, N);
if (min == 0) {
return 0;
}
if (L !=0 && O != 0) {
min = Math.min(min, L);
min = Math.min(min, O);
return min;
}
return 0;
}
``````

第二种解法

``````public int maxNumberOfBalloons2(String text) {
if (text == "" || text.length() < 7) {
return 0;
}
int A = 0, B = 0, L = 0, O = 0, N = 0;
int len = text.length();
int[] arr = new int[26];
for (int i=0; i<len; i++) {
arr[text.charAt(i)-'a']++;
}
A = arr[0];
B = arr[1];
L = arr[11]/2;
N = arr[13];
O = arr[14]/2;
int min = Math.min(A, B);
min = Math.min(min, N);
min = Math.min(min, L);
min = Math.min(min, O);
return min;
}
``````

第三种解法

``````public int maxNumberOfBalloons3(String text) {
if (text == "" || text.length() < 7) {
return 0;
}
int len = text.length();
int[] arr = new int[26];
for (int i=0; i<len; i++) {
arr[text.charAt(i)-'a']++;
}
int min = Math.min(arr[0], arr[1]); //a b
min = Math.min(min, arr[13]); // n
min = Math.min(min, arr[11]/2); // l
min = Math.min(min, arr[14]/2); // o
return min;
}
``````