7.7华为提前批笔试(更新题意)
1.有n个事件,每个事件形式为(t,w),表示若在t时刻前完成该事件,获得w分数,每一个小时只能完成一个事件,求最大能获得的分数
事件数量<=1000000
从后往前贪心 找到最大分值的任务并完成 tips:用long long类型存结果的最后得转int(数据应该是有点问题)
#include <algorithm> #include <cassert> #include <cmath> #include <cstdio> #include <cstdlib> #include <cstring> #include <ctime> #include <iostream> #include <map> #include <queue> #include <set> #include <stack> #include <unordered_map> #include <vector> #define fir first #define se second #define ll long long #define pb push_back #define mp make_pair #define ull unsigned long long #define cl(a, b) memset(a, b, sizeof(a)) #define quickio(a) ios::sync_with_stdio(a) #define datatest() freopen("data.in", "r", stdin) #define makeans() freopen("data.out", "w", stdout) #define makedata() freopen("data.in", "w", stdout) #define pii pair<int, int> #define pll pair<ll, ll> #define pdd pair<double, double> using namespace std; const int maxn = 1e6 + 10; const int maxm = 1e6 + 10; const int inf = 0x3f3f3f3f; const ll mod = 1e9 + 7; const int maxblock = sqrt(maxn) + 10; const double eps = 1e-7; const ll INF = 1e16; int n; pair<int, ll> p[maxn]; int cmp(pair<int, ll> &a, pair<int, ll> &b) { if (a.first != b.first) return a.first < b.first; else return a.second > b.second; } priority_queue<ll> pq; int main() { quickio(0); cin >> n; for (int i = 1; i <= n; i++) { cin >> p[i].first >> p[i].second; assert(p[i].first>0); assert(p[i].first<=1000000); assert(p[i].second > 0); } sort(p + 1, p + n + 1, cmp); ll res = 0; int cur = n; for (int t = 1000000; t >= 1; t--) { while (cur >= 1 && p[cur].first >= t) { if (p[cur].second > 0) { pq.push(p[cur].second); } cur--; } if (!pq.empty()) { ll top = pq.top(); res += top; pq.pop(); } } cout << (int)res << endl; return 0; }
2.给定一个有向图以及一个起点,问是否只从起点出发就可以走到全部的点,如果可以,输出起点到其他点的最长距离
点数<=100 边数<=5000
floyd求最长路然后判断找到最长路经就可以 最恶心的是输入
#include <algorithm> #include <cmath> #include <cstdio> #include <cstdlib> #include <cstring> #include <ctime> #include <iostream> #include <map> #include <queue> #include <set> #include <stack> #include <unordered_map> #include <vector> #define fir first #define se second #define ll long long #define pb push_back #define mp make_pair #define ull unsigned long long #define cl(a, b) memset(a, b, sizeof(a)) #define quickio(a) ios::sync_with_stdio(a) #define datatest() freopen("data.in", "r", stdin) #define makeans() freopen("data.out", "w", stdout) #define makedata() freopen("data.in", "w", stdout) #define pii pair<int, int> #define pll pair<ll, ll> #define pdd pair<double, double> using namespace std; const int maxn = 1e6 + 10; const int maxm = 1e6 + 10; const int inf = 0x3f3f3f3f; const ll mod = 1e9 + 7; const int maxblock = sqrt(maxn) + 10; const double eps = 1e-7; const ll INF = 1e16; vector<vector<int>> edge; int n, s; void ParseString(string &str) { int e[3]; cl(e, 0); int num = 0; int sz = str.size(); for (int i = 1; i < sz - 1; i++) { if (str[i] == ',') num++; else { e[num] = e[num] * 10 + str[i] - '0'; } } vector<int> temp{e[0], e[1], e[2]}; edge.emplace_back(temp); } vector<int> g[200]; int w[200][200]; int f[200][200]; int vis[200]; int dfs(int u) { vis[u] = 1; for (auto &v : g[u]) { if (vis[v] == 1) continue; dfs(v); } } map<int, int> ma; int main() { std::string str; int cnt = 0; while (cin >> str) { if (str[0] != '[') { if (cnt == 0) { n = stoi(str.c_str()); } else { s = stoi(str.c_str()); } cnt++; } else { ParseString(str); } } cl(f, inf); int cnt1 = 0; for (auto &it : edge) { int u = it[0], v = it[1], W = it[2]; if (!ma.count(u)) { ma[u] = ++cnt1; } if (!ma.count(v)) { ma[v] = ++cnt1; } } s = ma[s]; for (auto &it : edge) { int u = ma[it[0]], v = ma[it[1]], W = it[2]; g[u].push_back(v); f[u][v] = min(f[u][v], -1 * W); } for (int i = 1; i <= n; i++) f[i][i] = 0; //dfs(s); int num0 = 0; if (num0) { printf("-1\n"); return 0; } for (int k = 1; k <= n; k++) { for (int i = 1; i <= n; i++) { for (int j = 1; j <= n; j++) { f[i][j] = min(f[i][j], f[i][k] + f[k][j]); } } } for (int i = 1; i <= n; i++) num0 += (f[s][i] > 0); if (num0 > 0) { printf("-1\n"); return 0; } int Max = 0; for (int i = 1; i <= n; i++) { Max = min(Max, f[s][i]); } printf("%d\n", -1 * Max); return 0; }
3.二维网格图上给定一个起点一个终点,点的前进规则与中国象棋的马前进方式相同,问从起点到达终点的最小距离
地图长宽均<=150
普通的bfs即可
#include <algorithm> #include <cmath> #include <cstdio> #include <cstdlib> #include <cstring> #include <ctime> #include <iostream> #include <map> #include <queue> #include <set> #include <stack> #include <unordered_map> #include <vector> #define fir first #define se second #define ll long long #define pb push_back #define mp make_pair #define ull unsigned long long #define cl(a, b) memset(a, b, sizeof(a)) #define quickio(a) ios::sync_with_stdio(a) #define datatest() freopen("data.in", "r", stdin) #define makeans() freopen("data.out", "w", stdout) #define makedata() freopen("data.in", "w", stdout) #define pii pair<int, int> #define pll pair<ll, ll> #define pdd pair<double, double> using namespace std; const int maxn = 1e6 + 10; const int maxm = 1e6 + 10; const int inf = 0x3f3f3f3f; const ll mod = 1e9 + 7; const int maxblock = sqrt(maxn) + 10; const double eps = 1e-7; const ll INF = 1e16; int n, m; char str[200][200]; int legal(int x, int y, int n, int m) { if (x >= 1 && x <= n && y >= 1 && y <= m) return 1; return 0; } int vis[200][200]; int dis[200][200]; int dx[8] = {-2, -2, 2, 2, -1, -1, 1, 1}; int dy[8] = {-1, 1, -1, 1, -2, 2, -2, 2}; int footx[8] = {-1, -1, 1, 1, 0, 0, 0, 0}; int footy[8] = {0, 0, 0, 0, -1, 1, -1, 1}; int main() { scanf("%d %d", &n, &m); for (int i = 1; i <= n; i++) { scanf("%s", str[i] + 1); } pair<int, int> s, t; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { if (str[i][j] == 'H') { s = {i, j}; } if (str[i][j] == 'T') { t = {i, j}; } } } vis[s.first][s.second] = 1; queue<pair<int, int>> q; q.push(s); cl(dis, inf); dis[s.first][s.second] = 0; while (!q.empty()) { auto u = q.front(); q.pop(); int x = u.first, y = u.second; for (int i = 0; i < 8; i++) { int xx = x + dx[i]; int yy = y + dy[i]; if (legal(xx, yy, n, m) && !vis[xx][yy] && (str[xx][yy] != '#')) { int fx = x + footx[i]; int fy = y + footy[i]; if (legal(fx, fy, n, m) && str[fx][fy] == '#') { continue; } dis[xx][yy] = dis[x][y] + 1; vis[xx][yy] = 1; q.push(mp(xx, yy)); } } } if (dis[t.first][t.second] == inf) printf("-1\n"); else printf("%d\n", dis[t.first][t.second]); return 0; }