[Offer收割]编程练习赛63

命名

暴力

#include <bits/stdc++.h>
using namespace std;
char S[1111], T[1111], a[1111], b[1111];

int main() {
    int N;
    scanf("%d", &N);
    while(N--) {
        scanf("%s %s", S + 1, T + 1);
        int ls = strlen(S + 1), lt = strlen(T + 1), la = 0, lb = 0;
        for(int i = 1; i <= ls; ++i) {
            if(i % 2) a[++la] = S[i];
            else b[++lb] = S[i];
        }
        int pa = 1, pb = 1;
        for(int i = 1; i <= lt; ++i) {
            if(pa <= la && T[i] == a[pa]) pa++;
            if(pb <= lb && T[i] == b[pb]) pb++;
        }
        puts(pa > la || pb > lb ? "Yes" : "No");
    }
    return 0;
}

洗牌

暴力

#include <bits/stdc++.h>
using namespace std;
int a[1111];

void solve(int l, int r) {
    int m = (l + r) / 2;
    for (int i = l; i <= m; ++i) swap(a[i], a[m+i-l+1]);
    if (r - l > 1) solve(l, m), solve(m + 1, r);
}

int main() {
    int n, t;
    scanf("%d %d", &n, &t);
    for (int i = 1; i <= (1 << n); ++i) scanf("%d", a + i);
    if (t % 2 == 0) for (int i = 1; i <= (1 << n); ++i) printf("%d
", a[i]);
    else {
        solve(1, 1 << n);
        for (int i = 1; i <= (1 << n); ++i) printf("%d
", a[i]);
    }
    return 0;
}

密码更改

暴力

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
LL o, t, ans = -1, b;
char s[22];
int l;

LL dis(LL x, LL y) {
    return min(abs(x - y), b - abs(x - y));
}

int vis[10];
void dfs(int x) {
    if(x == l + 1) {
        if(ans == -1) ans = t;
        else if(dis(o, ans) < dis(o, t)) ans = t;
        else if(dis(o, ans) == dis(o, t) && t < ans) ans = t;
        return;
    }
    for(int i = 0; i <= 9; ++i) {
        if(vis[i]) continue;
        vis[i] = 1, t = t * 10 + i, dfs(x + 1);
        vis[i] = 0, t /= 10;
    }
}

void print(int x, LL y) {
    if(x != 1) print(x - 1, y / 10);
    printf("%lld", y % 10);
}

int main() {
    scanf("%s", s + 1);
    l = strlen(s + 1);
    b = 1;
    for(int i = 1; i <= l; ++i) b *= 10;
    sscanf(s + 1, "%lld", &o);
    dfs(1);
    print(l, ans);
    return 0;
}

道路摧毁

树dp

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const LL INF = 1e18;
const int maxn = 2e5 + 10;
vector<int> G[maxn], W[maxn];
int lab[maxn];

LL dp[maxn][3];
void dfs(int x, int f) {
    if(lab[x] == 1) dp[x][2] = INF;
    if(lab[x] == 2) dp[x][1] = INF;
    for(int i = 0; i < G[x].size(); ++i) {
        int to = G[x][i], w = W[x][i];
        if(to == f) continue;
        dfs(to, x);
        if(lab[x] != 1) dp[x][2] += min(dp[to][2], dp[to][1] + w);
        if(lab[x] != 2) dp[x][1] += min(dp[to][1], dp[to][2] + w);
    }
}

int main() {
    int n, o, mX, mY;
    scanf("%d", &n);
    scanf("%d", &mX);
    for(int i = 1; i <= mX; ++i) scanf("%d", &o), lab[o] = 1;
    scanf("%d", &mY);
    for(int i = 1; i <= mY; ++i) scanf("%d", &o), lab[o] = 2;
    for(int i = 1; i < n; ++i) {
        int u, v, w;
        scanf("%d %d %d", &u, &v, &w);
        G[u].push_back(v), W[u].push_back(w);
        G[v].push_back(u), W[v].push_back(w);
    }
    dfs(1, 0);
    printf("%lld
", min(dp[1][1], dp[1][2]));
    return 0;
}