- 模拟题
没注意第N次到的话特判，只能过96%
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int k=0,n=0;
String[] line = null;
if (sc.hasNextLine()) {
line = sc.nextLine().trim().split(" ");
k = Integer.parseInt(line[0]);
n = Integer.parseInt(line[1]);
}
if (sc.hasNextLine()) {
line = sc.nextLine().trim().split(" ");
}
int backNum = 0;
if (k == 0) {
System.out.println("paradox");
return;
}
for (String stepStr : line) {
int step = Integer.parseInt(stepStr);
if (step == k) {
System.out.println("paradox");
return;
}
if (step < k) {
k -= step;
} else {
backNum++;
k = step - k;
}
}
System.out.println(k + " " + backNum);
}
}
- 枚举+并查集
枚举错了 只过25%
public class Main {
static HashMap<String, String> map;
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
map = new HashMap<>(n);
while (sc.hasNextLine()) {
String line = sc.nextLine().trim().replace(" ","");
if (line.length() == 6)
map.put(line, line);
}
for (String str : map.keySet()) {
char[] chars = str.toCharArray();
for (int i = 0; i < 4; i++) {
char c4 = chars[4], c5 = chars[5];
chars[4] = chars[2];
chars[5] = chars[3];
chars[2] = c5;
chars[3] = c4;
String temp = String.valueOf(chars);
if (map.containsKey(temp)) {
union(str, temp);
}
char[] chars1 = temp.toCharArray();
for (int j = 0; j < 4; j++) {
char c0 = chars1[0], c1 = chars1[1];
chars1[0] = chars1[2];
chars1[1] = chars1[3];
chars1[2] = c1;
chars1[3] = c0;
String temp1 = String.valueOf(chars);
if (map.containsKey(temp1)) {
union(str, temp1);
}
char[] chars2 = temp1.toCharArray();
for (int k = 0; k < 4; k++) {
char c41 = chars2[4], c51 = chars2[5];
chars2[4] = chars2[0];
chars2[5] = chars2[1];
chars2[0] = c51;
chars2[1] = c41;
String temp2 = String.valueOf(chars2);
if (map.containsKey(temp2)) {
union(str, temp2);
}
}
}
}
chars = str.toCharArray();
for (int i = 0; i < 4; i++) {
char c0 = chars[0], c1 = chars[1];
chars[0] = chars[2];
chars[1] = chars[3];
chars[2] = c1;
chars[3] = c0;
String temp = String.valueOf(chars);
if (map.containsKey(temp)) {
union(str, temp);
}
char[] chars1 = temp.toCharArray();
for (int j = 0; j < 4; j++) {
char c01 = chars1[4], c11 = chars1[5];
chars1[4] = chars1[2];
chars1[5] = chars1[3];
chars1[2] = c11;
chars1[3] = c01;
String temp1 = String.valueOf(chars);
if (map.containsKey(temp1)) {
union(str, temp1);
}
char[] chars2 = temp1.toCharArray();
for (int k = 0; k < 4; k++) {
char c4 = chars2[4], c5 = chars2[5];
chars2[4] = chars2[0];
chars2[5] = chars2[1];
chars2[0] = c5;
chars2[1] = c4;
String temp2 = String.valueOf(chars2);
if (map.containsKey(temp2)) {
union(str, temp2);
}
}
}
}
chars = str.toCharArray();
for (int i = 0; i < 4; i++) {
char c4 = chars[4], c5 = chars[5];
chars[4] = chars[0];
chars[5] = chars[1];
chars[0] = c5;
chars[1] = c4;
String temp = String.valueOf(chars);
if (map.containsKey(temp)) {
union(str, temp);
}
char[] chars1 = temp.toCharArray();
for (int j = 0; j < 4; j++) {
char c0 = chars1[4], c1 = chars1[5];
chars1[4] = chars1[2];
chars1[5] = chars1[3];
chars1[2] = c1;
chars1[3] = c0;
String temp1 = String.valueOf(chars);
if (map.containsKey(temp1)) {
union(str, temp1);
}
char[] chars2 = temp1.toCharArray();
for (int k = 0; k < 4; k++) {
char c41 = chars2[0], c51 = chars2[1];
chars2[0] = chars2[2];
chars2[1] = chars2[3];
chars2[2] = c51;
chars2[3] = c41;
String temp2 = String.valueOf(chars2);
if (map.containsKey(temp2)) {
union(str, temp2);
}
}
}
}
}
for (String str : map.keySet()) {
String f = find(str);
map.put(str, f);
}
HashMap<String, Integer> counts = new HashMap<>();
for (Map.Entry<String, String> entry : map.entrySet()) {
counts.put(entry.getValue(), counts.getOrDefault(entry.getValue(), 0)+1);
}
int m = counts.size();
List<Integer> list = new ArrayList<>();
for (Map.Entry<String, Integer> entry : counts.entrySet()) {
list.add(entry.getValue());
}
list.sort((a, b) -> b - a);
System.out.println(m);
for (int i = 0; i < list.size()-1; i++) {
System.out.print(list.get(i)+" ");
}
System.out.print(list.get(list.size()-1));
}
public static void union(String s1, String s2) {
String f1 = find(s1), f2 = find(s2);
if (f1.compareTo(s2) <= 0) {
map.put(s2, f1);
} else {
map.put(s1, f2);
}
}
public static String find(String s) {
String f = map.get(s);
if (f.equals(s)) {
return s;
} else {
f = find(f);
map.put(s, f);
return f;
}
}
}
- 暴力只能过50%
但排序+剪枝能过到90%
最大最小问题 直接用二分做(不会)
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int m = sc.nextInt();
int t = sc.nextInt();
int[] lunchHeat = new int[n+1];
int[] lunchDesty = new int[n+1];
int[] dinnerHeat = new int[m+1];
int[] dinnerDesty = new int[m+1];
lunchHeat[0] = 0;
lunchDesty[0] = 0;
dinnerHeat[0] = 0;
dinnerDesty[0] = 0;
for (int i = 1; i <= n ; i++) {
lunchHeat[i] = sc.nextInt();
lunchDesty[i] = sc.nextInt();
}
for (int i = 1; i <= m; i++) {
dinnerHeat[i] = sc.nextInt();
dinnerDesty[i] = sc.nextInt();
}
int minHeat = Integer.MAX_VALUE;
for (int i = 0; i <= n; i++) {
for (int j = 0; j <= m; j++) {
if (lunchDesty[i] + dinnerDesty[j] >= t) {
minHeat = Math.min(minHeat, lunchHeat[i] + dinnerHeat[j]);
}
}
}
if (minHeat == Integer.MAX_VALUE) minHeat = -1;
System.out.println(minHeat);
}
}
4 插头dp 不会做
