将串t插入到串s的第u个位置开始的地方
时间: 2024-09-30 13:16:11 浏览: 15
将字符串t插入到字符串s的第u个位置开始,可以使用数组或字符串拼接的方式来实现。这里提供一种基于Python的示例:
```python
def insert_string(s, u, t):
# 确保索引u的有效性
if u < 0 or u > len(s):
raise ValueError("插入位置u无效")
# 如果u等于s的长度,直接在末尾添加t
if u == len(s):
return s + t
# 否则,将s分割成两部分,第一部分是前u个字符,第二部分是从第u+1到最后的字符
prefix = s[:u]
suffix = s[u:]
# 返回合并后的字符串
return prefix + t + suffix
# 示例:
s = "Hello"
u = 5
t = " World!"
result = insert_string(s, u, t)
print(result) # 输出: "Helloc World!"
```
相关问题
用c/c++实现,建立一个串,实现串的基本操作。主要有: 1)判串长: 返回串s的元素个数。 2)判空串: 若串s为空串,则返回true 3)串赋值:现有串s,空串 t,实现将s赋值给t的操作 4)串连接:现有串s和 t,实现将t链接到串s之后的操作。 5)串比较: 依次比较2个串s和t,若长度相同且字符相同,则串相同,返回0,若s>t,则返回值>0, 若s<t,则返回值<0. 6)串替换:在主串s中用子串v替换所有的子串t 7)串插入:在主串s中的给定位置pos插入子串t 8)取子串: 将串s中从起始位置pos开始长度len的字符串放入另一个串t 9)串删除: 删除串s中的子串t。 10)求子串位置:从主串s中取出从第i个位置开始、长度和串t相同的子串,和t进行比较,若相等,则t在s中的位置值为i。并在主函数中调用。
以下是用C语言实现的基本串操作:
1)判串长:
```c
int StrLength(char* s) {
int len = 0;
while (*s != '\0') {
len++;
s++;
}
return len;
}
```
2)判空串:
```c
bool IsEmpty(char* s) {
return (*s == '\0');
}
```
3)串赋值:
```c
void StrAssign(char* s, char* t) {
while (*t != '\0') {
*s = *t;
s++;
t++;
}
*s = '\0';
}
```
4)串连接:
```c
void StrConcat(char* s, char* t) {
while (*s != '\0') {
s++;
}
while (*t != '\0') {
*s = *t;
s++;
t++;
}
*s = '\0';
}
```
5)串比较:
```c
int StrCompare(char* s, char* t) {
while (*s == *t && *s != '\0') {
s++;
t++;
}
return (*s - *t);
}
```
6)串替换:
```c
void StrReplace(char* s, char* t, char* v) {
int len_t = StrLength(t);
int len_v = StrLength(v);
char* p = s;
while (*p != '\0') {
if (StrCompare(p, t) == 0) {
char* q = p + len_t;
char* r = v;
while (*r != '\0') {
*p = *r;
p++;
r++;
}
while (*q != '\0') {
*p = *q;
p++;
q++;
}
*p = '\0';
}
else {
p++;
}
}
}
```
7)串插入:
```c
void StrInsert(char* s, int pos, char* t) {
int len_s = StrLength(s);
int len_t = StrLength(t);
char* p = s + len_s;
char* q = s + pos;
while (p >= q) {
*(p + len_t) = *p;
p--;
}
while (*t != '\0') {
*q = *t;
q++;
t++;
}
*(s + len_s + len_t) = '\0';
}
```
8)取子串:
```c
void SubString(char* s, int pos, int len, char* t) {
int i;
for (i = 0; i < len; i++) {
*(t + i) = *(s + pos + i);
}
*(t + len) = '\0';
}
```
9)串删除:
```c
void StrDelete(char* s, char* t) {
int len_t = StrLength(t);
char* p = s;
while (*p != '\0') {
if (StrCompare(p, t) == 0) {
char* q = p + len_t;
while (*q != '\0') {
*p = *q;
p++;
q++;
}
*p = '\0';
}
else {
p++;
}
}
}
```
10)求子串位置:
```c
int Index(char* s, int i, char* t) {
int len_s = StrLength(s);
int len_t = StrLength(t);
char* p = s + i;
while (p <= s + len_s - len_t) {
if (StrCompare(p, t) == 0) {
return (p - s);
}
else {
p++;
}
}
return -1;
}
```
在主函数中调用:
```c
int main() {
char s[100] = "hello, world!";
char t[100] = "world";
char v[100] = "Lua closure factory";
char u[100] = "Chinese encryption";
printf("s = %s\n", s);
printf("t = %s\n", t);
printf("v = %s\n", v);
printf("u = %s\n", u);
printf("StrLength(s) = %d\n", StrLength(s));
printf("IsEmpty(s) = %d\n", IsEmpty(s));
StrAssign(t, s);
printf("StrAssign(t, s), t = %s\n", t);
StrConcat(s, v);
printf("StrConcat(s, v), s = %s\n", s);
printf("StrCompare(s, t) = %d\n", StrCompare(s, t));
StrReplace(s, t, v);
printf("StrReplace(s, t, v), s = %s\n", s);
StrInsert(s, 6, u);
printf("StrInsert(s, 6, u), s = %s\n", s);
SubString(s, 6, 6, t);
printf("SubString(s, 6, 6, t), t = %s\n", t);
StrDelete(s, t);
printf("StrDelete(s, t), s = %s\n", s);
printf("Index(s, 0, t) = %d\n", Index(s, 0, t));
return 0;
}
```
去掉注释:#include <iostream>#include <queue>#include <cstring>using namespace std;const int MAXN = 100005; // 最大字符串长度const int MAXM = 26; // 字符集大小struct AC_Automaton { int ch[MAXN][MAXM]; // Trie树 int val[MAXN]; // 节点值 int fail[MAXN]; // 失败指针 int tot; // 节点总数 void init() { memset(ch, 0, sizeof(ch)); memset(val, 0, sizeof(val)); memset(fail, 0, sizeof(fail)); tot = 0; } void insert(string s, int v) { // 插入字符串s,节点值为v int u = 0; for (int i = 0; i < s.size(); i++) { int c = s[i] - 'a'; if (!ch[u][c]) ch[u][c] = ++tot; u = ch[u][c]; } val[u] += v; } void build() { // 构建AC自动机 queue<int> q; for (int i = 0; i < MAXM; i++) { if (ch[0][i]) q.push(ch[0][i]); } while (!q.empty()) { int u = q.front(); q.pop(); for (int i = 0; i < MAXM; i++) { if (ch[u][i]) { fail[ch[u][i]] = ch[fail[u]][i]; q.push(ch[u][i]); } else { ch[u][i] = ch[fail[u]][i]; } } val[u] += val[fail[u]]; // 合并节点值 } } int query(string s) { // 查询字符串s中出现的模式串的节点值之和 int u = 0, res = 0; for (int i = 0; i < s.size(); i++) { u = ch[u][s[i] - 'a']; res += val[u]; } return res; }} AC;int main() { AC.init(); int n; cin >> n; for (int i = 1; i <= n; i++) { string s; int v; cin >> s >> v; AC.insert(s, v); } AC.build(); string t; cin >> t; cout << AC.query(t) << endl; return 0;}
#include <iostream>
#include <queue>
#include <cstring>
using namespace std;
const int MAXN = 100005; // 最大字符串长度
const int MAXM = 26; // 字符集大小
struct AC_Automaton {
int ch[MAXN][MAXM]; // Trie树
int val[MAXN]; // 节点值
int fail[MAXN]; // 失败指针
int tot; // 节点总数
void init() {
memset(ch, 0, sizeof(ch));
memset(val, 0, sizeof(val));
memset(fail, 0, sizeof(fail));
tot = 0;
}
void insert(string s, int v) { // 插入字符串s,节点值为v
int u = 0;
for (int i = 0; i < s.size(); i++) {
int c = s[i] - 'a';
if (!ch[u][c]) ch[u][c] = ++tot;
u = ch[u][c];
}
val[u] += v;
}
void build() { // 构建AC自动机
queue<int> q;
for (int i = 0; i < MAXM; i++) {
if (ch[0][i]) q.push(ch[0][i]);
}
while (!q.empty()) {
int u = q.front();
q.pop();
for (int i = 0; i < MAXM; i++) {
if (ch[u][i]) {
fail[ch[u][i]] = ch[fail[u]][i];
q.push(ch[u][i]);
} else {
ch[u][i] = ch[fail[u]][i];
}
}
val[u] += val[fail[u]]; // 合并节点值
}
}
int query(string s) { // 查询字符串s中出现的模式串的节点值之和
int u = 0, res = 0;
for (int i = 0; i < s.size(); i++) {
u = ch[u][s[i] - 'a'];
res += val[u];
}
return res;
}
} AC;
int main() {
AC.init();
int n;
cin >> n;
for (int i = 1; i <= n; i++) {
string s;
int v;
cin >> s >> v;
AC.insert(s, v);
}
AC.build();
string t;
cin >> t;
cout << AC.query(t) << endl;
return 0;
}