17164字符迁移

17164字符迁移

⭐️难度：中等
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import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int q = scanner.nextInt();
        scanner.nextLine();  // 清除行末的换行符
        String str = scanner.nextLine();
        char[] a = str.toCharArray();

       // 将字符串转换成数字 a -> 0,b -> 1
        int[] b = new int[n];
        for (int i = 0; i < n; i++) {
            b[i] = a[i] - 'a';
        }

        // 差分数组
        int[] diff = new int[n + 1];

        // 处理每次操作
        for (int i = 0; i < q; i++) {
            int l = scanner.nextInt();
            int r = scanner.nextInt();
            int k = scanner.nextInt();

            l--;r--; // 转换成 0 基索引

            k %= 26;

            diff[l] += k;
            diff[r + 1] -= k;
        }

        // 应用差分数组
        int sum = 0; // 求前缀和
        for (int i = 0; i < n; i++) {
            sum += diff[i];
            // 计算最终的移位数，确保结果在 [0, 25] 范围内
            int sum2 = (sum + b[i]) % 26;
            // 重新转换回字符串
            b[i] = sum2;
        }

        for (int i = 0; i < n; i++) {
            System.out.print((char)(b[i] + 'a'));
        }
        
        scanner.close();
    }
}

⭕️

1. k有可能很大，要对26取余。

 k %= 26;

2. 计算最终的移位数，确保结果在 [0, 25] 范围内

 int sum2 = (sum + b[i]) % 26;