Poj 2513 colored sticks (Euler's path + query set + dictionary tree)

Link: poj 2513 colored sticks

There are n wooden sticks, each of which is painted with a color. Now, the color of each wooden stick is given.

Finally, I asked if I could splice n wooden sticks together.

Solution: Euler's path + query set + dictionary tree. Euler's path. The statistical degree of each node. The number of vertices with an odd degree cannot exceed 2. Check the set and determine the node

Whether it is fully connected. Dictionary tree, ing color.

#include <cstdio>#include <cstring>#include <string>#include <vector>#include <iostream>#include <algorithm>using namespace std;const int maxn = 5000005;const int sigma_size = 26;typedef pair<int,int> pii;int N, E, far[maxn], cnt[maxn];pii ed[maxn];struct Tire {    int sz, g[maxn][sigma_size];    int val[maxn];    void init();    int idx(char ch);    int insert(char* s);}T;inline int getfar(int x) {    return x == far[x] ? x : far[x] = getfar(far[x]);}bool judge() {    int ret = 0;    for (int i = 1; i <= N; i++) {        if (cnt[i]&1)            ret++;    }    if (ret > 2)        return false;    for (int i = 0; i < E; i++) {        int p = getfar(ed[i].first);        int q = getfar(ed[i].second);        if (p != q) {            N--;            far[p] = q;        }    }    return N <= 1;}int main () {    T.init();    N = E = 0;    char a[11], b[11];    while (scanf("%s%s", a, b) == 2) {        int p = T.insert(a);        int q = T.insert(b);        cnt[p]++, cnt[q]++;        ed[E].first = p;        ed[E].second = q;        E++;    }    printf("%s\n", judge() ? "Possible" : "Impossible");    return 0;}void Tire::init() {    sz = 1;    val[0] = 0;    memset(g[0], 0, sizeof(g[0]));}int Tire::idx(char ch) {    return ch - ‘a‘;}int Tire::insert(char* s) {    int u = 0, n = strlen(s);    for (int i = 0; i < n; i++) {        int v = idx(s[i]);        if (g[u][v] == 0) {            g[u][v] = sz;            memset(g[sz], 0, sizeof(g[sz]));            val[sz++] = 0;        }        u = g[u][v];    }    if (val[u] == 0) {        val[u] = ++N;        far[N] = N;        cnt[N] = 0;    }    return val[u];}

Poj 2513 colored sticks (Euler's path + query set + dictionary tree)