Knowee
Questions
Features
Study Tools

You are given a sequence [a1,โ€ฆ,an][๐‘Ž1,โ€ฆ,๐‘Ž๐‘›] where each element ai๐‘Ž๐‘– is either 00 or 11. You can apply several (possibly zero) operations to the sequence. In each operation, you select two integers 1โ‰คlโ‰คrโ‰ค|a|1โ‰ค๐‘™โ‰ค๐‘Ÿโ‰ค|๐‘Ž| (where |a||๐‘Ž| is the current length of a๐‘Ž) and replace [al,โ€ฆ,ar][๐‘Ž๐‘™,โ€ฆ,๐‘Ž๐‘Ÿ] with a single element x๐‘ฅ, where x๐‘ฅ is the majority of [al,โ€ฆ,ar][๐‘Ž๐‘™,โ€ฆ,๐‘Ž๐‘Ÿ].Here, the majority of a sequence consisting of 00 and 11 is defined as follows: suppose there are c0๐‘0 zeros and c1๐‘1 ones in the sequence, respectively.If c0โ‰ฅc1๐‘0โ‰ฅ๐‘1, the majority is 00.If c0<c1๐‘0<๐‘1, the majority is 11.For example, suppose a=[1,0,0,0,1,1]๐‘Ž=[1,0,0,0,1,1]. If we select l=1,r=2๐‘™=1,๐‘Ÿ=2, the resulting sequence will be [0,0,0,1,1][0,0,0,1,1]. If we select l=4,r=6๐‘™=4,๐‘Ÿ=6, the resulting sequence will be [1,0,0,1][1,0,0,1].Determine if you can make a=[1]๐‘Ž=[1] with a finite number of operations.InputEach test contains multiple test cases. The first line contains the number of test cases t๐‘ก (1โ‰คtโ‰ค4โ‹…1041โ‰ค๐‘กโ‰ค4โ‹…104). Description of the test cases follows.The first line of each testcase contains one integer n๐‘› (1โ‰คnโ‰ค2โ‹…1051โ‰ค๐‘›โ‰ค2โ‹…105).The second line of each testcase contains a string consisting of 00 and 11, describing the sequence a๐‘Ž.It's guaranteed that the sum of n๐‘› over all testcases does not exceed 2โ‹…1052โ‹…105.OutputFor each testcase, if it's possible to make a=[1]๐‘Ž=[1], print YES. Otherwise, print NO. You can output the answer in any case (upper or lower). For example, the strings yEs, yes, Yes, and YES will be recognized as positive responses.ExampleinputCopy5101120191000000019000011000outputCopyNoYesNoYesNoNoteIn the fourth testcase of the example, initially a=[1,0,0,0,0,0,0,0,1]๐‘Ž=[1,0,0,0,0,0,0,0,1]. A valid sequence of operations is:Select l=2,r=8๐‘™=2,๐‘Ÿ=8 and apply the operation. a๐‘Ž becomes [1,0,1][1,0,1].Select l=1,r=3๐‘™=1,๐‘Ÿ=3 and apply the operation. a๐‘Ž becomes [1][1].

Question

You are given a sequence [a1,โ€ฆ,an][๐‘Ž1,โ€ฆ,๐‘Ž๐‘›] where each element ai๐‘Ž๐‘– is either 00 or 11. You can apply several (possibly zero) operations to the sequence. In each operation, you select two integers 1โ‰คlโ‰คrโ‰ค|a|1โ‰ค๐‘™โ‰ค๐‘Ÿโ‰ค|๐‘Ž| (where |a||๐‘Ž| is the current length of a๐‘Ž) and replace [al,โ€ฆ,ar][๐‘Ž๐‘™,โ€ฆ,๐‘Ž๐‘Ÿ] with a single element x๐‘ฅ, where x๐‘ฅ is the majority of [al,โ€ฆ,ar][๐‘Ž๐‘™,โ€ฆ,๐‘Ž๐‘Ÿ].Here, the majority of a sequence consisting of 00 and 11 is defined as follows: suppose there are c0๐‘0 zeros and c1๐‘1 ones in the sequence, respectively.If c0โ‰ฅc1๐‘0โ‰ฅ๐‘1, the majority is 00.If c0<c1๐‘0<๐‘1, the majority is 11.For example, suppose a=[1,0,0,0,1,1]๐‘Ž=[1,0,0,0,1,1]. If we select l=1,r=2๐‘™=1,๐‘Ÿ=2, the resulting sequence will be [0,0,0,1,1][0,0,0,1,1]. If we select l=4,r=6๐‘™=4,๐‘Ÿ=6, the resulting sequence will be [1,0,0,1][1,0,0,1].Determine if you can make a=[1]๐‘Ž=[1] with a finite number of operations.InputEach test contains multiple test cases. The first line contains the number of test cases t๐‘ก (1โ‰คtโ‰ค4โ‹…1041โ‰ค๐‘กโ‰ค4โ‹…104). Description of the test cases follows.The first line of each testcase contains one integer n๐‘› (1โ‰คnโ‰ค2โ‹…1051โ‰ค๐‘›โ‰ค2โ‹…105).The second line of each testcase contains a string consisting of 00 and 11, describing the sequence a๐‘Ž.It's guaranteed that the sum of n๐‘› over all testcases does not exceed 2โ‹…1052โ‹…105.OutputFor each testcase, if it's possible to make a=[1]๐‘Ž=[1], print YES. Otherwise, print NO. You can output the answer in any case (upper or lower). For example, the strings yEs, yes, Yes, and YES will be recognized as positive responses.ExampleinputCopy5101120191000000019000011000outputCopyNoYesNoYesNoNoteIn the fourth testcase of the example, initially a=[1,0,0,0,0,0,0,0,1]๐‘Ž=[1,0,0,0,0,0,0,0,1]. A valid sequence of operations is:Select l=2,r=8๐‘™=2,๐‘Ÿ=8 and apply the operation. a๐‘Ž becomes [1,0,1][1,0,1].Select l=1,r=3๐‘™=1,๐‘Ÿ=3 and apply the operation. a๐‘Ž becomes [1][1].

...expand
๐Ÿง Not the exact question you are looking for?Go ask a question

Solution

The problem is asking to determine if it's possible to make a sequence of 0s and 1s into a sequence containing only a single 1 through a series of operations. In each operation, you select a subsequence and replace it with the majority element. The majority element is defined as 0 if there are more or

Similar Questions

You are given an array ๐ดA containing ๐‘N integers.Consider the following process:Let ๐‘†=0S=0 initially.For each ๐‘–i from 11 to ๐‘N in order, update ๐‘†S to either (๐‘†+๐ด๐‘–)(S+A iโ€‹ ) or (๐‘†ร—๐ด๐‘–)(Sร—A iโ€‹ ).That is, either add ๐ด๐‘–A iโ€‹ to ๐‘†S or multiply ๐‘†S by ๐ด๐‘–A iโ€‹ .Before performing the process, you're allowed to freely rearrange the elements of ๐ดA as you like.If you choose the rearrangement of ๐ดA and the sequence of operations optimally, what's the maximum possible value of ๐‘†S that you can obtain?This maximum value can be very large, so print it modulo 109+710 9 +7.Input FormatThe first line of input will contain a single integer ๐‘‡T, denoting the number of test cases.Each test case consists of two lines of input.The first line of each test case contains a single integer ๐‘N โ€” the number of elements in the array.The second line contains ๐‘N space-separated integers ๐ด1,๐ด2,โ€ฆ,๐ด๐‘A 1โ€‹ ,A 2โ€‹ ,โ€ฆ,A Nโ€‹ - the elements of the array.Output FormatFor each test case, output on a new line the maximum possible value of ๐‘†S, modulo 109+710 9 +7.Constraints1โ‰ค๐‘‡โ‰ค1031โ‰คTโ‰ค10 3 1โ‰ค๐‘โ‰ค2โ‹…1051โ‰คNโ‰ค2โ‹…10 5 1โ‰ค๐ด๐‘–โ‰ค1091โ‰คA iโ€‹ โ‰ค10 9 The sum of ๐‘N over all test cases won't exceed 2โ‹…1052โ‹…10 5 .Sample 1:InputOutput244 2 5 231 2 1804Explanation:Test case 11: Choose the rearrangement ๐ด=[2,2,5,4]A=[2,2,5,4]. Then,Add ๐ด1=2A 1โ€‹ =2 to ๐‘†S. Now, ๐‘†=2S=2.Add ๐ด2=2A 2โ€‹ =2 to ๐‘†S. Now, ๐‘†=4S=4.Multiply ๐‘†S by ๐ด3=5A 3โ€‹ =5. Now, ๐‘†=20S=20.Multiply ๐‘†S by ๐ด4=4A 4โ€‹ =4. Now, ๐‘†=80S=80.This is the maximum value that can be obtained.Test case 22: Choose any rearrangement and sum up all the numbers to get 1+1+2=41+1+2=4.This is the maximum value that can be obtained.

Suppose a sequence an, is de๏ฌned as follows:a1 = 9/10, a2 = 10/11, an+2 = an+1an

You are given a positive integer x๐‘ฅ. Find any array of integers a0,a1,โ€ฆ,anโˆ’1๐‘Ž0,๐‘Ž1,โ€ฆ,๐‘Ž๐‘›โˆ’1 for which the following holds:1โ‰คnโ‰ค321โ‰ค๐‘›โ‰ค32,ai๐‘Ž๐‘– is 11, 00, or โˆ’1โˆ’1 for all 0โ‰คiโ‰คnโˆ’10โ‰ค๐‘–โ‰ค๐‘›โˆ’1,x=โˆ‘i=0nโˆ’1aiโ‹…2i๐‘ฅ=โˆ‘๐‘–=0๐‘›โˆ’1๐‘Ž๐‘–โ‹…2๐‘–,There does not exist an index 0โ‰คiโ‰คnโˆ’20โ‰ค๐‘–โ‰ค๐‘›โˆ’2 such that both aiโ‰ 0๐‘Ž๐‘–โ‰ 0 and ai+1โ‰ 0๐‘Ž๐‘–+1โ‰ 0.It can be proven that under the constraints of the problem, a valid array always exists.InputEach test contains multiple test cases. The first line of input contains a single integer t๐‘ก (1โ‰คtโ‰ค1041โ‰ค๐‘กโ‰ค104)ย โ€” the number of test cases. The description of the test cases follows.The only line of each test case contains a single positive integer x๐‘ฅ (1โ‰คx<2301โ‰ค๐‘ฅ<230).OutputFor each test case, output two lines.On the first line, output an integer n๐‘› (1โ‰คnโ‰ค321โ‰ค๐‘›โ‰ค32)ย โ€” the length of the array a0,a1,โ€ฆ,anโˆ’1๐‘Ž0,๐‘Ž1,โ€ฆ,๐‘Ž๐‘›โˆ’1.On the second line, output the array a0,a1,โ€ฆ,anโˆ’1๐‘Ž0,๐‘Ž1,โ€ฆ,๐‘Ž๐‘›โˆ’1.If there are multiple valid arrays, you can output any of them.ExampleinputCopy71142415271119outputCopy1150 -1 0 0 160 0 0 -1 0 15-1 0 0 0 16-1 0 -1 0 0 15-1 0 -1 0 15-1 0 1 0 1NoteIn the first test case, one valid array is [1][1], since (1)โ‹…20=1(1)โ‹…20=1.In the second test case, one possible valid array is [0,โˆ’1,0,0,1][0,โˆ’1,0,0,1], since (0)โ‹…20+(โˆ’1)โ‹…21+(0)โ‹…22+(0)โ‹…23+(1)โ‹…24=โˆ’2+16=14(0)โ‹…20+(โˆ’1)โ‹…21+(0)โ‹…22+(0)โ‹…23+(1)โ‹…24=โˆ’2+16=14.

Suppose a sequence an, is defined as follows: a1 = 9/10, a2 = 10/11, an+2 = an+1an.Show that 0 < an < 1 for all (positive integers) n.

You are given two integer arrays: array a๐‘Ž of length n๐‘› and array b๐‘ of length n+1๐‘›+1.You can perform the following operations any number of times in any order:choose any element of the array a๐‘Ž and increase it by 11;choose any element of the array a๐‘Ž and decrease it by 11;choose any element of the array a๐‘Ž, copy it and append the copy to the end of the array a๐‘Ž.Your task is to calculate the minimum number of aforementioned operations (possibly zero) required to transform the array a๐‘Ž into the array b๐‘. It can be shown that under the constraints of the problem, it is always possible.InputThe first line contains a single integer t๐‘ก (1โ‰คtโ‰ค1041โ‰ค๐‘กโ‰ค104)ย โ€” the number of test cases.Each test case consists of three lines:the first line contains a single integer n๐‘› (1โ‰คnโ‰ค2โ‹…1051โ‰ค๐‘›โ‰ค2โ‹…105);the second line contains n๐‘› integers a1,a2,โ€ฆ,an๐‘Ž1,๐‘Ž2,โ€ฆ,๐‘Ž๐‘› (1โ‰คaiโ‰ค1091โ‰ค๐‘Ž๐‘–โ‰ค109);the third line contains n+1๐‘›+1 integers b1,b2,โ€ฆ,bn+1๐‘1,๐‘2,โ€ฆ,๐‘๐‘›+1 (1โ‰คbiโ‰ค1091โ‰ค๐‘๐‘–โ‰ค109).Additional constraint on the input: the sum of n๐‘› over all test cases doesn't exceed 2โ‹…1052โ‹…105.OutputFor each test case, print a single integerย โ€” the minimum number of operations (possibly zero) required to transform the array a๐‘Ž into the array b๐‘.ExampleinputCopy3121 323 33 3 344 2 1 22 1 5 2 3outputCopy318NoteIn the first example, you can transform a๐‘Ž into b๐‘ as follows: [2]โ†’[2,2]โ†’[1,2]โ†’[1,3][2]โ†’[2,2]โ†’[1,2]โ†’[1,3].

1/2

Upgrade your grade with Knowee

Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.