C++程式檢查字串是否已出現
假設我們有一個包含n個字串的陣列'stringArr'。我們逐個迭代字串元素,找出陣列中是否之前出現過該字串。如果出現,則列印'已出現!',否則列印'未出現!'
問題類別
為了解決這個問題,我們需要操作字串。程式語言中的字串是由儲存在特定陣列型別資料中的字元流組成。一些語言將字串指定為特定資料型別(例如Java、C++、Python);而其他一些語言則將字串指定為字元陣列(例如C)。字串在程式設計中非常重要,因為它們通常是各種應用程式中首選的資料型別,並用作輸入和輸出的資料型別。有各種字串操作,例如字串搜尋、子串生成、字串剝離操作、字串轉換操作、字串替換操作、字串反轉操作等等。檢視下面的連結,瞭解如何在C/C++中使用字串。
https://tutorialspoint.tw/cplusplus/cpp_strings.htm
https://tutorialspoint.tw/cprogramming/c_strings.htm
因此,如果我們問題的輸入類似於n = 6,s = {"apple", "dog", "cat", "mouse", "apple", "cat"},則輸出將為
Didn't see before! Didn't see before! Didn't see before! Didn't see before! Seen Before. Seen Before.
步驟
為了解決這個問題,我們將遵循以下步驟:
Define one set s
for initialize i := 0, when i < n, update (increase i by 1), do:
if stringArr[i] is present in s, then:
print("Seen Before.")
Otherwise
print("Didn't see before!")
insert stringArr[i] into s示例
讓我們看下面的實現來更好地理解:
#include<bits/stdc++.h>
using namespace std;
void solve(int n, string stringArr[]) {
set<string> s;
for(int i = 0; i < n; i++) {
if(s.count(stringArr[i]))
cout << "Seen Before." << endl;
else{
cout<< "Didn't see before!" <<endl;
s.insert(stringArr[i]);
}
}
}
int main() {
int n = 6;
string s[] = {"apple", "dog", "cat", "mouse", "apple", "cat"};
solve(n, s);
return 0;
}輸入
6, {"apple", "dog", "cat", "mouse", "apple", "cat"}輸出
Didn't see before! Didn't see before! Didn't see before! Didn't see before! Seen Before. Seen Before.
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