A、Brain’s Photos
給一個
暴力判斷,時間複雜度:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <climits>
#include <cmath>
#include <ctime>
#include <cassert>
#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
typedef long long ll;
const int MAX_N = 110;
int n, m;
int main()
{
while (~scanf("%d%d", &n, &m)) {
int flag = 0;
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
char s[5];
scanf("%s", s);
if (s[0] == 'C' || s[0] == 'M' || s[0] == 'Y'){
flag = 1;
}
}
}
if (flag) printf("#Color\n");
else printf("#Black&White\n");
}
return 0;
}
B、Bakery
給
如果存在最短距離的話,一定是一條邊的兩個端點,只要判斷是否存在這樣的邊然後取最短即可。
也可以不用先
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <climits>
#include <cmath>
#include <ctime>
#include <cassert>
#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
typedef long long ll;
const int MAX_N = 100010;
int n, m, k;
int vis[MAX_N];
struct Edge {
int u, v, w;
bool operator < (const Edge& rhs) const {
return w < rhs.w;
}
} edge[MAX_N];
int main()
{
while (~scanf("%d%d%d", &n, &m, &k)) {
memset(vis, 0, sizeof(vis));
for (int i = 0; i < m; ++i) {
int u, v, w;
scanf("%d%d%d", &u, &v, &w);
edge[i].u = u, edge[i].v = v;
edge[i].w = w;
}
sort(edge, edge + m);
for (int i = 0; i < k; ++i) {
int u;
scanf("%d", &u);
vis[u] = 1;
}
int ans = -1;
for (int i = 0; i < m; ++i) {
int u = edge[i].u, v = edge[i].v, w = edge[i].w;
if (vis[u] && !vis[v]) ans = w;
if (vis[v] && !vis[u]) ans = w;
if (ans != -1) break;
}
printf("%d\n", ans);
}
return 0;
}
C、Pythagorean Triples
給一個
當
當
當
當
時間複雜度:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <climits>
#include <cmath>
#include <ctime>
#include <cassert>
#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
typedef long long ll;
int n;
ll m;
void solve()
{
m = 1ll * n * n;
if (n == 1 || n == 2) printf("-1\n");
else if (m % 4 == 0) printf("%I64d %I64d\n", m / 4 - 1, m / 4 + 1);
else if (m & 1) printf("%I64d %I64d\n", (m - 1) / 2, (m - 1) / 2 + 1);
}
int main()
{
while (~scanf("%d", &n)) {
solve();
}
return 0;
}
D、Persistent Bookcase
給一個
1 i j :如果第i 排的第j 個位置是空的,就放一本書上去。2 i j :如果第i 排的第j 個位置上有書,那就把這本書取下來。3 i :將第i 排的所有位置狀態顛倒:有書的位置把書取下,沒書的位置放上書。4 i :回到第i 個操作時的狀態,初始狀態是第0 操作。
對於每次操作輸出書架上書的總數量。
數據範圍:
最基本的for循環就是最簡單、最顯式的dfs
如果沒有第四種操作,直接按照題意for循環下去即可。對於第四種操作可以記錄每個操作的兒子(後繼操作),然後dfs下去並還原即可,注意細節。
藉助
時間複雜度:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <climits>
#include <cmath>
#include <ctime>
#include <cassert>
#include <vector>
#include <set>
#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
typedef long long ll;
const int MAX_Q = 100010;
const int MAX_N = 1010;
int n, m, Q;
vector<int> children[MAX_Q];
set<int> s[MAX_N];
int cnt[MAX_N];
struct Query {
int type, x, y, ans;
} query[MAX_Q];
void init()
{
for (int i = 0; i <= n; ++i) {
children[i].clear();
s[i].clear();
cnt[i] = 0;
}
}
// cnt[x] 爲奇:s[x]是不存在的;cnt[x]爲偶:s[x]是存在的
void dfs(int cur, int sum)
{
int type = query[cur].type, x = query[cur].x, y = query[cur].y, flag = 0;
if (type == 1) {
if (cnt[x] % 2 == 0 && s[x].find(y) == s[x].end()) {
s[x].insert(y);
sum++;
flag = 1;
} else if (cnt[x] % 2 && s[x].find(y) != s[x].end()) {
s[x].erase(y);
sum++;
flag = 1;
}
} else if (type == 2) {
if (cnt[x] % 2 == 0 && s[x].find(y) != s[x].end()) {
s[x].erase(y);
sum--;
flag = 1;
} else if (cnt[x] % 2 && s[x].find(y) == s[x].end()) {
s[x].insert(y);
sum--;
flag = 1;
}
} else if (type == 3) {
if (cnt[x] % 2 == 0) {
sum -= s[x].size();
sum += (m - s[x].size());
} else {
sum -= (m - s[x].size());
sum += s[x].size();
}
cnt[x]++;
flag = 1;
}
// printf("cur = %d x = %d y = %d sum = %d\n", cur, x, y, sum);
query[cur].ans = sum;
for (int i = 0; i < children[cur].size(); ++i) {
dfs(children[cur][i], sum);
}
if (flag) {
if (type == 1) {
if (cnt[x] % 2 == 0) s[x].erase(y);
else s[x].insert(y);
sum--;
} else if (type == 2) {
if (cnt[x] % 2 == 0) s[x].insert(y);
else s[x].erase(y);
sum++;
} else { // type = 3
if (cnt[x] % 2 == 0) {
sum -= s[x].size();
sum += (m - s[x].size());
} else {
sum -= (m - s[x].size());
sum += s[x].size();
}
cnt[x]--;
}
}
}
int main()
{
while (~scanf("%d%d%d", &n, &m, &Q)) {
init();
for (int i = 1; i <= Q; ++i) {
query[i].y = -1;
scanf("%d%d", &query[i].type, &query[i].x);
if (query[i].type < 3) {
scanf("%d", &query[i].y);
}
if (query[i].type == 4) {
children[query[i].x].push_back(i);
} else {
children[i - 1].push_back(i);
}
}
for (int i = 0; i < children[0].size(); ++i) {
dfs(children[0][i], 0);
}
for (int i = 1; i <= Q; ++i) {
printf("%d\n", query[i].ans);
}
}
return 0;
}
E、Garlands
給一個
- 改變第
i 個花環:開變關,關變開 - 求左上角下標爲
(a,b) ,右下角下標爲(c,d) 的矩形內所有開着的花的價值之和。
對於每個第二種操作,輸出相應價值和。
數據範圍:
這也太暴力了。
直接上二維樹狀數組,對於每種花環的狀態記錄類似於
時間複雜度:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <climits>
#include <cmath>
#include <ctime>
#include <cassert>
#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
typedef long long ll;
const int MAX_N = 2010;
int n, m, K, Q;
int num[MAX_N], cur[MAX_N], state[MAX_N];
ll C[MAX_N][MAX_N];
struct Garland {
int x, y, w;
} garland[MAX_N][MAX_N];
inline int lowbit(int x)
{
return x & (-x);
}
void update(int x, int y, int w)
{
for(int i = x; i <= n; i += lowbit(i)) {
for (int j = y; j <= m; j += (lowbit(j))) {
C[i][j] += w;
}
}
}
ll sum(int x, int y)
{
ll res = 0;
for (int i = x; i > 0; i -= lowbit(i)) {
for (int j = y; j > 0; j -= lowbit(j)) {
res += C[i][j];
}
}
return res;
}
int main()
{
while (~scanf("%d%d%d", &n, &m, &K)) {
memset(state, 0, sizeof(state));
memset(cur, 0, sizeof(cur));
memset(C, 0, sizeof(C));
for (int i = 0; i < K; ++i) {
scanf("%d", &num[i]);
for (int j = 0; j < num[i]; ++j) {
int x, y, w;
scanf("%d%d%d", &x, &y, &w);
garland[i][j].x = x, garland[i][j].y = y, garland[i][j].w = w;
update(x, y, w);
}
}
scanf("%d", &Q);
for (int i = 0; i < Q; ++i) {
char s[10];
scanf("%s", s);
if (s[0] == 'S') {
int id;
scanf("%d", &id);
id--;
state[id] ^= 1; // 細節!
cur[id] ^= 1;
} else {
int a, b, c, d;
scanf("%d%d%d%d", &a, &b, &c, &d);
for (int i = 0; i < K; ++i) {
if (state[i] == 0) continue;
int flag = 1;
if (cur[i] == 1) flag = -1;
state[i] = 0;
for (int j = 0; j < num[i]; ++j) {
int x = garland[i][j].x, y = garland[i][j].y, w = garland[i][j].w;
update(x, y, flag * w);
}
}
ll ans = sum(c, d) + sum(a - 1, b - 1) - sum(c, b - 1) - sum(a - 1, d);
printf("%lld\n", ans);
}
}
}
return 0;
}