Question

我正在尝试UVa问题编号10324 我编写了以下解决方案，这得到了一个接受，但给出了一个非常糟糕的运行时间2.670秒 我有以下两个代码这是我的代码

    public static void main(String[] args) throws Exception{
        // write your code here
        StringBuilder op = new StringBuilder();
            InputStreamReader isr = new InputStreamReader(System.in);
            BufferedReader reader = new BufferedReader(isr);
            String input, tmp[];
            int n, l, u, j, i = 0;
            boolean dec;
            char thi;
            while ((input = reader.readLine()) != null) {
                op.append("Case " + (++i) + ":\n");
                n = Integer.parseInt(reader.readLine());
                while (n-- > 0) {
                    tmp = reader.readLine().split(" ");
                    l = Integer.parseInt(tmp[0]);
                    u = Integer.parseInt(tmp[1]);
                    if (l > u) {
                        l ^= u;
                        u ^= l;
                        l ^= u;
                    }
                    //System.out.println(l + "|" + u);
                    dec = true;
                    thi = input.charAt(l++);
                    for (; l <= u; l++) {
                        if (thi != input.charAt(l)||(thi != input.charAt(u--))) {
                            dec = false;
                            break;
                        }
                    }
                    op.append((dec ? "Yes\n" : "No\n"));
                }
            }
            System.out.print(op.toString());
            return;

    }
}

，其他代码是我在Mr Gorgon's Solution找到的代码这个运行时间为0.84秒

public static void main(String[] args) throws Exception {
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
    StringBuilder sb = new StringBuilder("");
    int testCase = 1;
    String line;
    while ((line = br.readLine()) != null) {
        sb.append("Case ").append(testCase).append(":\n");
        testCase++;
        int noOfCases = Integer.parseInt(br.readLine());
        for (int j = 0; j < noOfCases; j++) {
            String[] str = br.readLine().split(" ");
            int val1 = Integer.parseInt(str[0]);
            int val2 = Integer.parseInt(str[1]);
            if (val1 > val2) {
                val1 ^= val2;
                val2 ^= val1;
                val1 ^= val2;
            }
            boolean isValid = true;
            if (val1 != val2) {
                for (int i = val1; i < val2; i++) {
                    if (line.charAt(i) != line.charAt(i + 1)) {
                        isValid = false;
                        break;
                    }
                }
            }
            if (isValid)
                sb.append("Yes\n");
            else
                sb.append("No\n");
        }
    }
    System.out.print(sb);
}

我发现很难理解当所有任务基本相同时，为什么这段代码运行得更快。我的代码声明比Gorgons代码更少

Answer 1

op.append("Case " + (++i) + ":\n");

这否定了StringBuilder的好处

if (val1 != val2) {在第二个版本中，快捷方式是循环

Answer 2

它的

   TreeContainer = Backbone.Model.extend({
                elementCount: 0,
                file: '',
                object: {jj: "kk"},
                type: "input",
                parent: d3.select("#canvas"),
                initialize: function () {
                    var result = this.readFile();
                    for (var i = 0; i < 200; i++) {
                        console.log(i); //this is resulted before the readFile content
                    }

                },
                readFile: function () {
                    var model = this;
                    // display text
                    if (this.get('file').name.endsWith(".json") || this.get('file').type === "application/json") {

                        var reader = new FileReader();

                        reader.onload = function (e) {
                            //parseJSON
                            var text = e.target.result;
                            var data = JSON.parse(text);
                            model.set('object', data);
                            console.log(data);
                            return data;
                        };
                        reader.readAsText(this.get('file'));
                    }
                }
            });

这有助于加快程序，我认为它与缓存

有关

我研究并发现了一些名为 JCS 的内容这可能允许他们的apache服务器修复内存数据并帮助更快地访问

Answer 3

您的解决方案中缺少下面的代码。你正在盲目地循环，好像条件限制循环。

if (val1 != val2) {
                                    }
            }

java的速度为什么有些代码运行得更快

3 个答案: