题解 | 字符串操作

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scanner=new Scanner(System.in);
		int n=scanner.nextInt();
		int m=scanner.nextInt();
		String string=scanner.next();
		for (int i = 0; i < m; i++) {
			int l=scanner.nextInt();
			int r=scanner.nextInt();
			char c1=scanner.next().charAt(0);
			char c2=scanner.next().charAt(0);
			for (int j = l-1; j < r; j++) {
				if(string.charAt(j)==c1) {
					string=string.substring(0,j)+c2+string.substring(j+1);
				}
			}
		}
		System.out.println(string);

	}

}

本题其实可以将字符串转换为字符数组做，但是我写了一半才想到，就算了。我直接采用substring剪切字符串，，再拼接，这里需要注意substring是左闭右开的用法