英文:
Reverse leftover
问题
我正在处理一个程序，该程序读取一串字符，并根据一个数字对某些字符进行反转。
（例如，给定“TELLER”和3，应返回“LETREL”）
我遇到的问题是，我需要反转剩下的额外字符。
（例如，给定“HELLO”和3，它返回“LEHLO”，但我需要它返回“LEHOL”）
以下是我当前尝试的方法：
for (int i = 0; i < st.length();) {
if (i + x > st.length()-1){
break;
}
st = st.substring(0, i) + new String(new StringBuilder(st.substring(i, i + x)).reverse()) + st.substring(i + x);
i += x; }
英文:
I am working on a program that reads a string of characters and reverses certain characters based off a number.
(i.e. "TELLER" and 3 is given, it should return "LETREL)
The problem I am running into is that I need to reverse the extra characters left over
(i.e. "HELLO" and 3 is given, it returns "LEHLO" when I need it to return "LEHOL")
This is how i'm currently trying to go about it
for (int i = 0; i < st.length();) {
if (i + x > st.length()-1){
break;
}
st = st.substring(0, i) + new String(new StringBuilder(st.substring(i, i + x)).reverse()) + st.substring(i + x);
i += x; }
答案1
得分: 2
String input = "Hello";
StringBuilder buffer = new StringBuilder();
int x = 3;
for (int d = 0; d < Math.floor(input.length() / x); d++) {
buffer.append(new StringBuilder(input.substring(d * x, (d + 1) * x)).reverse());
}
if (input.length() % x != 0)
buffer.append(new StringBuilder(input.substring(input.length() - input.length() % x - 1)).reverse());
System.out.println("Result is " + buffer.toString());
英文:
String input = "Hello";
StringBuilder buffer = new StringBuilder();
int x = 3;
for(int d = 0; d < Math.floor(input.length / x); d++){
buffer.append((new StringBuilder(input.substring(d * x, (d + 1) * x))).reverse());
}
if(input.length % x != 0) buffer.append((new StringBuilder(input.substring(input.length - input.length % x - 1))).reverse());
System.out.println("Result is " + buffer.toString());
答案2
得分: 0
尝试以下内容。应该可以正常工作。
for (int i = 0; i < st.length();) {
if (i + x > st.length() - 1){
s += new String(new StringBuilder(st.substring(i, st.length())).reverse());
break;
}
s += new String(new StringBuilder(st.substring(i, i + x)).reverse());
i += x;
}
如果有任何部分你不理解，请告诉我。祝编码愉快！
英文:
Try the following. It should work.
for (int i = 0; i < st.length();) {
if (i + x > st.length()-1){
s += new String(new StringBuilder(st.substring(i, st.length())).reverse());
break;
}
s += new String(new StringBuilder(st.substring(i, i + x)).reverse());
i += x;
}
Let me know if you don't understand any part. Happy coding!
答案3
得分: 0
// 字符串拼接，+ 和 +=，会创建多个字符串对象。
// 同时，按给定步长遍历字符串会更容易：
StringBuilder reversed = new StringBuilder(st.length);
for (int i = 0; i + x <= st.length(); i += x) {
int nextI = Math.min(i + x, st.length());
for (int j = i; j < nextI; ++j) {
reversed.insert(i, st.charAt(j));
}
}
s = reversed.toString();
或者
for (int i = 0; i < st.length(); ) {
int nextI = Math.min(i + x, st.length());
for (int j = i; j < nextI; ++j) {
reversed.insert(i, st.charAt(j));
}
i = nextI;
}
英文:
String concatenation, + and +=, is expensive as several String-s are created.
Also it would be easier to step through the string in the given step size:
StringBuilder reversed = new StringBuilder(st.length);
for (int i = 0; i + x <= st.length(); i += x) {
int nextI = Math.min(i + x, st.length());
for (int j = i; j < nextI; ++j) {
reversed.insert(i, st.charAt(j));
}
}
s = reversed.toString();
Or
for (int i = 0; i < st.length(); ) {
int nextI = Math.min(i + x, st.length());
for (int j = i; j < nextI; ++j) {
reversed.insert(i, st.charAt(j));
}
i = nextI;
}
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