• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>

            oyjpArt ACM/ICPC算法程序設計空間

            // I am new in programming, welcome to my blog
            I am oyjpart(alpc12, 四城)
            posts - 224, comments - 694, trackbacks - 0, articles - 6

            PKU1925 Spiderman 【DP】

            Posted on 2007-04-05 20:41 oyjpart 閱讀(2326) 評論(2)  編輯 收藏 引用 所屬分類: ACM/ICPC或其他比賽

            Spiderman
            Time Limit:5000MS  Memory Limit:65536K
            Total Submit:1762 Accepted:197

            Description
            Dr. Octopus kidnapped Spiderman's girlfriend M.J. and kept her in the West Tower. Now the hero, Spiderman, has to reach the tower as soon as he can to rescue her, using his own weapon, the web.

            From Spiderman's apartment, where he starts, to the tower there is a straight road. Alongside of the road stand many tall buildings, which are definitely taller or equal to his apartment. Spiderman can shoot his web to the top of any building between the tower and himself (including the tower), and then swing to the other side of the building. At the moment he finishes the swing, he can shoot his web to another building and make another swing until he gets to the west tower. Figure-1 shows how Spiderman gets to the tower from the top of his apartment – he swings from A to B, from B to C, and from C to the tower. All the buildings (including the tower) are treated as straight lines, and during his swings he can't hit the ground, which means the length of the web is shorter or equal to the height of the building. Notice that during Spiderman's swings, he can never go backwards.


            You may assume that each swing takes a unit of time. As in Figure-1, Spiderman used 3 swings to reach the tower, and you can easily find out that there is no better way.

             

            Input
            The first line of the input contains the number of test cases K (1 <= K <= 20). Each case starts with a line containing a single integer N (2 <= N <= 5000), the number of buildings (including the apartment and the tower). N lines follow and each line contains two integers Xi, Yi, (0 <= Xi, Yi <= 1000000) the position and height of the building. The first building is always the apartment and the last one is always the tower. The input is sorted by Xi value in ascending order and no two buildings have the same X value.

            Output
            For each test case, output one line containing the minimum number of swings (if it's possible to reach the tower) or -1 if Spiderman can't reach the tower.

            Sample Input

            2
            6
            0 3
            3 5
            4 3
            5 5
            7 4
            10 4
            3
            0 3
            3 4
            10 4
            

             

            Sample Output

            3
            -1
            

             

            Source
            Beijing 2004 Preliminary@POJ

            這是DP題,根據坐標DP是比較好的選擇,提交中wa多次。經回復指點 才注意到建筑物高度相乘越界了 謝謝提醒了

            //Solution by oyjpArt
            #include <stdio.h>
            #include <math.h>
            #include <string.h>
            const int N = 5010;
            const int M = 1000010;
            int x[N], y[N], dp[M], nb;
            const int MAXINT = 2000000000;
            #define Min(a,b) ((a) < (b) ? (a) : (b))

            int main() {
             int ntc, i, j;
             scanf("%d", &ntc);
             while(ntc--) {
              scanf("%d", &nb);
              for(i = 0; i<nb; i++)  scanf("%d %d", x+i, y+i);
              int m = x[nb-1];
              memset(dp, -1, (m+1)*sizeof(dp[0]));
              dp[x[0]] = 0;
              double h = y[0]; 
              for(i = 1; i<nb; i++) { //以1..i的建筑為中介進行飛行
               int d = sqrt(2*y[i]*h - h*h); //不會墜落到地上的最長距離 sqrt(y[i]*y[i]-sqare(y[i]-h))
               for(j = 1; j<=d; j++) { //DP
                if(x[i]-j < x[0]) break; //無用狀態
                if(dp[x[i]-j] == -1) continue; //不可達
                int k = x[i]+j < m ? x[i]+j : m;
                if(dp[k] == -1) dp[k] = dp[x[i]-j]+1;
                else dp[k] = Min(dp[k], dp[x[i]-j]+1);
               }//for
              }//for
              printf("%d\n", dp[m]);
             }
             return 0;
            }

            Feedback

            # re: PKU1925 Spiderman 【DP】  回復  更多評論   

            2007-04-11 15:24 by mark
            int的話相乘后可能越界了

            # re: PKU1925 Spiderman 【DP】  回復  更多評論   

            2007-04-16 20:53 by oyjpart
            謝謝提醒 呵呵
            亚洲欧洲中文日韩久久AV乱码| AAA级久久久精品无码区| 99久久国产综合精品五月天喷水 | 无码任你躁久久久久久| 欧美无乱码久久久免费午夜一区二区三区中文字幕 | 久久精品国产精品青草| 久久不射电影网| 亚洲伊人久久成综合人影院 | 国产精品一区二区久久不卡| 91精品国产综合久久精品| 99久久婷婷国产综合精品草原| 热久久视久久精品18| 精品久久无码中文字幕| 美女久久久久久| 777久久精品一区二区三区无码| 热99RE久久精品这里都是精品免费 | 情人伊人久久综合亚洲| 久久精品免费网站网| 97久久超碰成人精品网站| 精品久久久久久久久久中文字幕| 无码日韩人妻精品久久蜜桃| 91精品国产综合久久四虎久久无码一级| 久久免费国产精品| 1000部精品久久久久久久久| 亚洲欧美国产精品专区久久| 国产人久久人人人人爽| 人妻精品久久久久中文字幕69 | 国产综合久久久久| 亚洲中文字幕久久精品无码APP | 99久久久精品免费观看国产| 久久久久免费精品国产| 亚洲国产成人乱码精品女人久久久不卡 | 久久精品青青草原伊人| 久久久精品久久久久久| 国产精品日韩深夜福利久久 | 999久久久免费国产精品播放| 国产精品久久午夜夜伦鲁鲁| 亚洲女久久久噜噜噜熟女| 久久无码专区国产精品发布| 久久综合久久综合亚洲| 久久久久国产精品嫩草影院|