P4391 [BOI2009] Radio Transmission 无线传输

合集 - 思维题(99)

1.大雪球2024-01-16 2.E. Final Countdown2024-02-18 3.D. Divisible Pairs2024-02-19 4.F. Chat Screenshots2024-02-19 5.G. One-Dimensional Puzzle2024-02-20 6.P8775 [蓝桥杯 2022 省 A] 青蛙过河2024-02-21 7.Watering an Array2024-02-23 8.Dora and Search2024-02-24 9.P1137 旅行计划2024-02-24 10.P3067 [USACO12OPEN] Balanced Cow Subsets G2024-02-26 11.P4799 [CEOI2015 Day2] 世界冰球锦标赛2024-02-26 12.A. Brick Wall2024-02-28 13.B. Minimize Inversions2024-02-28 14.C. XOR-distance2024-02-28 15.A. Moving Chips2024-02-28 16.B. Monsters Attack!2024-02-28 17.C. Find B2024-02-28 18.D. Slimes2024-02-28 19.C. Turtle Fingers: Count the Values of k2024-02-28 20.D. Turtle Tenacity: Continual Mods2024-02-28 21.D. Vlad and Division2024-02-28 22.C. LR-remainders2024-02-28 23.P5322 [BJOI2019] 排兵布阵2024-03-03 24.P2946 [USACO09MAR] Cow Frisbee Team S2024-03-03 25.P1156 垃圾陷阱2024-03-03 26.P1064 [NOIP2006 提高组] 金明的预算方案2024-03-04 27.P3047 [USACO12FEB] Nearby Cows G2024-03-04 28.P5020 [NOIP2018 提高组] 货币系统2024-03-04 29.P3957 [NOIP2017 普及组] 跳房子2024-03-06 30.P1550 [USACO08OCT] Watering Hole G2024-03-06 31.P1525 [NOIP2010 提高组] 关押罪犯2024-03-07 32.P1379 八数码难题2024-03-07 33.P6121 [USACO16OPEN] Closing the Farm G2024-03-08 34.P2341 [USACO03FALL / HAOI2006] 受欢迎的牛 G2024-03-08 35.P9632 [ICPC2020 Nanjing R] K Co-prime Permutation2024-03-08 36.P9825 [ICPC2020 Shanghai R] Fibonacci2024-03-08 37.P2034 选择数字2024-03-09 38.P7072 [CSP-J2020] 直播获奖2024-03-09 39.P1714 切蛋糕2024-03-09 40.P4147 玉蟾宫2024-03-10 41.P2866 [USACO06NOV] Bad Hair Day S2024-03-10 42.P2032 扫描2024-03-10 43.P1884 [USACO12FEB] Overplanting S2024-03-10 44.D. Lonely Mountain Dungeons2024-03-12 45.F. Microcycle2024-03-12 46.E. Increasing Subsequences__22024-03-13 47.D. Valiant's New Map2024-03-14 48.Array Repetition2024-03-14 49.F. Rudolf and Imbalance2024-03-14 50.D. Exam in MAC2024-03-15 51.G. Rudolf and Subway2024-03-15 52.C. Ehab and Path-etic MEXs2024-03-17 53.A. String Transformation 12024-03-17 54.D. Solve The Maze2024-03-18 55.B. Array Fix2024-03-18 56.B. Equal XOR2024-03-18 57.F. Maximum White Subtree2024-03-19 58.P1652 圆2024-03-20 59.P2181 对角线2024-03-20 60.P1325 雷达安装2024-03-20 61.P3194 [HNOI2008] 水平可见直线2024-03-20 62.B - Make Many Triangles2024-03-23 63.[ARC172A] Chocolate2024-03-25 64.C. Theofanis' Nightmare2024-03-27 65.D. Birthday Gift2024-03-27 66.C. Arrow Path2024-03-27 67.P1265 公路修建2024-03-28 68.P1284 三角形牧场2024-03-28 69.Kirill and Mushrooms2024-03-28 70.C. Sasha and the Casino2024-03-28 71.P1470 [USACO2.3] 最长前缀 Longest Prefix2024-04-01 72.P5536 【XR-3】核心城市2024-04-02 73.P5836 [USACO19DEC] Milk Visits S2024-04-02

74.P4391 [BOI2009] Radio Transmission 无线传输2024-04-04

75.P3435 [POI2006] OKR-Periods of Words2024-04-04 76.P5960 【模板】差分约束2024-04-04 77.P3052 [USACO12MAR] Cows in a Skyscraper G2024-04-05 78.E. Long Inversions2024-04-09 79.C. Deep Down Below2024-04-09 80.C. Rings2024-04-09 81.F. Unfair Game2024-04-10 82.G. GCD on a grid2024-04-10 83.C. Inversion Graph2024-04-10 84.Increase Subarray Sums2024-04-10 85.D. Cross Coloring2024-04-12 86.M. Triangle Construction2024-04-12 87.D2. Set To Max (Hard Version)2024-04-12 88.C. Array Game2024-04-12 89.F. Alex's whims2024-04-12 90.Queue Sort2024-04-12 91.P1908 逆序对2024-04-13 92.P5094 [USACO04OPEN] MooFest G 加强版2024-04-15 93.P5149 会议座位2024-04-15 94.P10337 [UESTCPC 2024] 操作序列2024-04-15 95.P10330 [UESTCPC 2024] 黑白珠串2024-04-15 96.P10252 线性变换2024-04-16 97.P3901 数列找不同2024-04-16 98.P10288 [GESP样题八级] 区间2024-04-16 99.P5677 [GZOI2017] 配对统计2024-04-17

原题链接

题解

1.当 $s_{2}$ 长度大于等于 $s_{1}$ 时，我们就令 $s 2$ 的长度为 $n$
2.当 $l e n (s_{2}) < n$ 时，我们令此时的 $s_{2}$ 无法被自我链接形成，为什么要这么设？

3.此时的 $s_{1}$ 与 $s_{2}$ 的关系一定张这样，为什么 $s_{2}$ 一定开头重合？因为我们可以把不重合的后半部分与前半部分叠起来成为一个新 $s_{2}$

观察到后半部分往前移动 $l e n (s_{2})$ 个单位长度后与前半部分重叠，也就是最长公共前后缀长度等于 $n - l e n (s_{2})$ 的性质

code

#include<bits/stdc++.h>
using namespace std;
int lps[1000005]={0};
int main()
{
    int n;
    cin>>n;
    char s[1000006];
    cin>>(s+1);
    lps[0]=-1;
    int it=0;
    for(int i=2;i<=n;i++)
    {
        while(it>=0&&s[i]!=s[it+1]) it=lps[it];//查找最长相等前后缀，it代表i-1的已经匹配成功的相等前后缀长度（下标），it大于等于0的才有意义
        lps[i]=++it;//匹配成功，长度加一
    }

    cout<<n-lps[n];
    return 0;
}