[hihocoder] [Offer收割]编程练习赛43

版本号排序

不知道什么傻逼原因，就是过不了

#pragma comment(linker, "/STACK:102400000,102400000")
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<vector>
#include<algorithm>
#include<iostream>
#include<map>
#include<queue>
#include<stack>
#include<string>
#include<functional>
#include<math.h>
//#include<bits/stdc++.h>
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
void makedata() {
    freopen("input.txt", "w", stdout);
    cout << 200000 << endl;

    for(int i = 0; i < 200000; i++) cout << 1000000000 << ‘ ‘;

    fclose(stdout);
}

VI a[200];
bool ok(int x, int y) {
    int lx = a[x].size(), ly = a[y].size();
    int l = min(lx, ly);

    for(int i = 0; i < l; i++) {
        if(a[x][i] < a[y][i]) return true;

        if(a[x][i] > a[y][i]) return false;
    }

    if(lx <= ly) return true;
    else return false;
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n;
    cin >> n;

    for(int i = 0; i < n; i++) {
        int tmp;
        cin >> tmp;
        a[i].push_back(tmp);

        while(getchar() == ‘.‘) {
            cin >> tmp;
            a[i].push_back(tmp);
        }
    }

    for(int i = 0; i < n; i++) {
        for(int j = i + 1; j < n; j++) {
            if(!ok(i, j)) swap(a[i], a[j]);
        }
    }

    for(int i = 0; i < n; i++) {
        cout << a[i][0];

        for(int j = 1; j < a[i].size(); j++) cout << ‘.‘ << a[i][j];

        cout << endl;
    }

    return 0;
}

自底向上遍历二叉树

叶节点从左到右的顺序就是它们在树的从上到下的遍历中的顺序，按遍历中的顺序不断向上找

#pragma comment(linker, "/STACK:102400000,102400000")
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<vector>
#include<algorithm>
#include<iostream>
#include<map>
#include<queue>
#include<stack>
#include<string>
#include<functional>
#include<math.h>
//#include<bits/stdc++.h>
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
void makedata() {
    freopen("input.txt", "w", stdout);
    cout << 200000 << endl;

    for(int i = 0; i < 200000; i++) cout << 1000000000 << ‘ ‘;

    fclose(stdout);
}

VI ch[110000];
bool f[110000];
int father[110000];
void traverse(int x) {
    while(f[x] == false && x) {
        cout << x << endl;
        f[x] = true;
        x = father[x];
    }
}
void dfs(int x) {
    if(ch[x].size() == 0) traverse(x);
    else for(int i = 0; i < ch[x].size(); i++) dfs(ch[x][i]);
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n;
    cin >> n;
    memset(father, 0, sizeof(father));

    for(int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        father[v] = u;
        ch[u].push_back(v);
    }

    for(int i = 1; i <= n; i++) {
        if(ch[i].size() != 2) continue;

        if(ch[i][0] > ch[i][1]) {
            int tmp = ch[i][0];
            ch[i][0] = ch[i][1];
            ch[i][1] = tmp;
        }
    }

    int root = 1;

    while(father[root]) root = father[root];

    memset(f, false, sizeof(f));
    dfs(root);
    return 0;
}

hiho字符串2

根据长度dfs，注意一开始是第1代而不是第0代。

#pragma comment(linker, "/STACK:102400000,102400000")
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<vector>
#include<algorithm>
#include<iostream>
#include<map>
#include<queue>
#include<stack>
#include<string>
#include<functional>
#include<math.h>
//#include<bits/stdc++.h>
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
void makedata() {
    freopen("input.txt", "w", stdout);
    cout << 200000 << endl;

    for(int i = 0; i < 200000; i++) cout << 1000000000 << ‘ ‘;

    fclose(stdout);
}

lint L[256][200];
const lint INF = (1LL << 40);

char dfs(string s, int n, lint k) {
    char ch = s[0];
    int len = s.size();
    string ss;

    if(n == 0) {
        if(k > len) return 0;
        else return s[k - 1];
    }

    if(L[ch][n] >= k) {
        if(ch == ‘h‘) ss = "hio";

        if(ch == ‘i‘) ss = "hi";

        if(ch == ‘o‘) ss = "ho";

        return dfs(ss, n - 1, k);
    } else {
        k -= L[ch][n];
        ss = s.substr(1, len - 1);
        return dfs(ss, n, k);
    }
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    L[‘h‘][0] = L[‘i‘][0] = L[‘o‘][0] = 1;

    for(int i = 1; i <= 150; i++) {
        L[‘h‘][i] = L[‘h‘][i - 1] + L[‘i‘][i - 1] + L[‘o‘][i - 1];
        L[‘i‘][i] = L[‘h‘][i - 1] + L[‘i‘][i - 1];
        L[‘o‘][i] = L[‘h‘][i - 1] + L[‘o‘][i - 1];

        if(L[‘h‘][i] > INF) L[‘h‘][i] = INF;

        if(L[‘i‘][i] > INF) L[‘i‘][i] = INF;

        if(L[‘o‘][i] > INF) L[‘o‘][i] = INF;
    }

    int t, n;
    lint k;
    cin >> t;
    string s = "hiho";

    while(t--) {
        cin >> n >> k;
        cout << dfs(s, n - 1, k) << endl;;
    }

    return 0;
}

最长多数子串

一开始想的是二分+hash，没过。别人用的SAM，想破了脑袋也想不清楚。以前看过SAM，当时看完就觉得：“好叼啊，可是有什么用啊？”，怎么也想不通在哪里能用上，这里别人用了，怎么也想不通到底怎么过的。

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<memory>
#include<cmath>
#define maxn 2000003
using namespace std;
int n, m, len, ans, Max, now;
char s[maxn], cap[maxn];
struct SAM {
    int ch[maxn][26], fa[maxn], maxlen[maxn], Last, sz;
    int root, nxt[maxn], size[maxn];
    void init() {
        sz = 0;
        root = ++sz;
        memset(size, 0, sizeof(size));
        memset(ch[1], 0, sizeof(ch[1]));
        memset(nxt, 0, sizeof(nxt));
    }
    void add(int x) {
        int np = ++sz, p = Last;
        Last = np;
        memset(ch[np], 0, sizeof(ch[np]));
        maxlen[np] = maxlen[p] + 1;
        while (p && !ch[p][x]) ch[p][x] = np, p = fa[p];
        if (!p) fa[np] = 1;
        else {
            int q = ch[p][x];
            if (maxlen[p] + 1 == maxlen[q]) fa[np] = q;
            else {
                int nq = ++sz;
                memcpy(ch[nq], ch[q], sizeof(ch[q]));
                size[nq] = size[q];
                nxt[nq] = nxt[q];
                maxlen[nq] = maxlen[p] + 1;
                fa[nq] = fa[q];
                fa[q] = fa[np] = nq;
                while (p && ch[p][x] == q) ch[p][x] = nq, p = fa[p];
            }
        }
        for (; np; np = fa[np])
            if (nxt[np] != now) {
                size[np]++;
                nxt[np] = now;
            } else break;
    }
};
SAM Sam;
int main() {
    while (~scanf("%d%d", &n, &m) && n) {
        Sam.init();
        for (int i = 1; i <= n; i++) {
            scanf("%s", s + 1);
            Sam.Last = Sam.root;
            len = strlen(s + 1);
            now = i;
            for (int j = 1; j <= len; j++) Sam.add(s[j] - ‘a‘);
        }
        Max = 0;
        ans = 0;
        for (int i = 1; i <= Sam.sz; i++)
            if (Sam.size[i] >= m && Sam.maxlen[i] > ans) {
                Max = i;
                ans = Sam.maxlen[i];
            }
        printf("%d\n", ans);
    }
    return 0;
}

原文地址：https://www.cnblogs.com/dramstadt/p/8251562.html