第1讲思维训练.pptx

算法设计与分析-思维训练;例题1 勇者斗恶龙（The Dragon of Loowater, UVa 11292）;对于每组数据，输出最少花费。如果无解，输出“Loowater is doomed!”。;11 Loowater is doomed!;#includecstdio #includealgorithm //因为用到了sort using namespace std; const int maxn = 20000 + 5; int A[maxn], B[maxn]; int main() { int n, m; while(scanf(%d%d, n, m) == 2 n m) { for(int i = 0; i n; i++) scanf(%d, A[i]); for(int i = 0; i m; i++) scanf(%d, B[i]); sort(A, A+n); sort(B, B+m); int cur = 0; //当前需要砍掉的头的编号 int cost = 0; //当前总费用 for(int i = 0; i m; i++) if(B[i] = A[cur]) { cost += B[i]; //雇佣该骑士 if(++cur == n) break; //如果头已经砍完，及时退出循环 } if(cur n) printf(Loowater is doomed!\n); else printf(%d\n, cost); } return 0; } ;例题2 突击战（Commando War, UVa 11729）;对于每组数据，输出所有任务完成的最短时间。;3 2 5 3 2 2 1 3 3 3 4 4 5 5 0;#includecstdio #includevector #includealgorithm using namespace std; struct Job { int j, b; bool operator (const Job x) const { //运算符重载。不要忘记const修饰符 return j x.j; } }; int main() { int n, b, j, kase = 1; while(scanf(%d, n) == 1 n) { vectorJob v; for(int i = 0; i n; i++) { scanf(%d%d, b, j); v.push_back((Job){j,b}); } sort(v.begin(), v.end()); //使用Job类自己的 运算符排序 int s = 0; int ans = 0; for(int i = 0; i n; i++) { s += v[i].b; //当前任务的开始执行时间 ans = max(ans, s+v[i].j); //更新任务执行完毕时的最晚时间 } printf(Case %d: %d\n, kase++, ans); } return 0; } ;例题3 分金币（Spreading the Wealth, UVa 11300）;对于每组数据，输出被转手金币数量的最小值。输入保证这个值在64位无符号整数范围内。;3 100 100 100 4 1 2 5 4;#includecstdio #includealgorithm using namespace std; const int maxn = 1000000 + 10; long long A[maxn], C[maxn], tot, M; int main() { int n; while(scanf(%d, n) == 1) { //输入数据大，scanf比cin快 tot = 0; for(int i = 1; i = n; i++) { scanf(%lld, A[i]); tot += A[i]; } //用%lld输入long long M = tot / n; C[0] = 0; for(int i = 1; i n; i++) C[i] = C[i-1] + A[i] - M; //递推C数组 sort(C, C+n); long